diff --git a/.coveragerc b/.coveragerc
deleted file mode 100644
index 13baa100b84b7..0000000000000
--- a/.coveragerc
+++ /dev/null
@@ -1,30 +0,0 @@
-# .coveragerc to control coverage.py
-[run]
-branch = False
-omit = */tests/*
-plugins = Cython.Coverage
-
-[report]
-# Regexes for lines to exclude from consideration
-exclude_lines =
-    # Have to re-enable the standard pragma
-    pragma: no cover
-
-    # Don't complain about missing debug-only code:
-    def __repr__
-    if self\.debug
-
-    # Don't complain if tests don't hit defensive assertion code:
-    raise AssertionError
-    raise NotImplementedError
-    AbstractMethodError
-
-    # Don't complain if non-runnable code isn't run:
-    if 0:
-    if __name__ == .__main__.:
-
-ignore_errors = False
-show_missing = True
-
-[html]
-directory = coverage_html_report
diff --git a/pandas/_libs/algos.pyx b/pandas/_libs/algos.pyx
index 249033b8636bd..415e7026e09c8 100644
--- a/pandas/_libs/algos.pyx
+++ b/pandas/_libs/algos.pyx
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 from libc.stdlib cimport malloc, free
 from libc.string cimport memmove
@@ -114,7 +114,7 @@ cpdef ndarray[int64_t, ndim=1] unique_deltas(ndarray[int64_t] arr):
 
 @cython.wraparound(False)
 @cython.boundscheck(False)
-def is_lexsorted(list list_of_arrays):
+def is_lexsorted(list_of_arrays: list) -> bint:
     cdef:
         Py_ssize_t i
         Py_ssize_t n, nlevels
diff --git a/pandas/_libs/hashing.pyx b/pandas/_libs/hashing.pyx
index 88b4d97de492c..c2305c8f3ff00 100644
--- a/pandas/_libs/hashing.pyx
+++ b/pandas/_libs/hashing.pyx
@@ -3,7 +3,6 @@
 # at https://github.com/veorq/SipHash
 
 import cython
-from cpython cimport PyBytes_Check, PyUnicode_Check
 from libc.stdlib cimport malloc, free
 
 import numpy as np
@@ -44,6 +43,7 @@ def hash_object_array(object[:] arr, object key, object encoding='utf8'):
         char **vecs
         char *cdata
         object val
+        list datas = []
 
     k = <bytes>key.encode(encoding)
     kb = <uint8_t *>k
@@ -57,12 +57,11 @@ def hash_object_array(object[:] arr, object key, object encoding='utf8'):
     vecs = <char **> malloc(n * sizeof(char *))
     lens = <uint64_t*> malloc(n * sizeof(uint64_t))
 
-    cdef list datas = []
     for i in range(n):
         val = arr[i]
-        if PyBytes_Check(val):
+        if isinstance(val, bytes):
             data = <bytes>val
-        elif PyUnicode_Check(val):
+        elif isinstance(val, unicode):
             data = <bytes>val.encode(encoding)
         elif val is None or is_nan(val):
             # null, stringify and encode
@@ -132,15 +131,6 @@ cdef inline void _sipround(uint64_t* v0, uint64_t* v1,
     v2[0] = _rotl(v2[0], 32)
 
 
-# TODO: This appears unused; remove?
-cpdef uint64_t siphash(bytes data, bytes key) except? 0:
-    if len(key) != 16:
-        raise ValueError("key should be a 16-byte bytestring, "
-                         "got {key} (len {klen})"
-                         .format(key=key, klen=len(key)))
-    return low_level_siphash(data, len(data), key)
-
-
 @cython.cdivision(True)
 cdef uint64_t low_level_siphash(uint8_t* data, size_t datalen,
                                 uint8_t* key) nogil:
diff --git a/pandas/_libs/index.pyx b/pandas/_libs/index.pyx
index d5846f2b42378..562c1ba218141 100644
--- a/pandas/_libs/index.pyx
+++ b/pandas/_libs/index.pyx
@@ -1,10 +1,7 @@
 # -*- coding: utf-8 -*-
 from datetime import datetime, timedelta, date
 
-cimport cython
-
-from cpython cimport PyTuple_Check, PyList_Check
-from cpython.slice cimport PySlice_Check
+import cython
 
 import numpy as np
 cimport numpy as cnp
@@ -30,15 +27,15 @@ cdef int64_t iNaT = util.get_nat()
 
 
 cdef inline bint is_definitely_invalid_key(object val):
-    if PyTuple_Check(val):
+    if isinstance(val, tuple):
         try:
             hash(val)
         except TypeError:
             return True
 
     # we have a _data, means we are a NDFrame
-    return (PySlice_Check(val) or util.is_array(val)
-            or PyList_Check(val) or hasattr(val, '_data'))
+    return (isinstance(val, slice) or util.is_array(val)
+            or isinstance(val, list) or hasattr(val, '_data'))
 
 
 cpdef get_value_at(ndarray arr, object loc, object tz=None):
@@ -88,7 +85,7 @@ cdef class IndexEngine:
             void* data_ptr
 
         loc = self.get_loc(key)
-        if PySlice_Check(loc) or util.is_array(loc):
+        if isinstance(loc, slice) or util.is_array(loc):
             return arr[loc]
         else:
             return get_value_at(arr, loc, tz=tz)
@@ -640,7 +637,7 @@ cdef class BaseMultiIndexCodesEngine:
     def get_loc(self, object key):
         if is_definitely_invalid_key(key):
             raise TypeError("'{key}' is an invalid key".format(key=key))
-        if not PyTuple_Check(key):
+        if not isinstance(key, tuple):
             raise KeyError(key)
         try:
             indices = [0 if checknull(v) else lev.get_loc(v) + 1
diff --git a/pandas/_libs/internals.pyx b/pandas/_libs/internals.pyx
index 996570dae3302..681530ed494d7 100644
--- a/pandas/_libs/internals.pyx
+++ b/pandas/_libs/internals.pyx
@@ -1,10 +1,9 @@
 # -*- coding: utf-8 -*-
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 from cpython cimport PyObject
-from cpython.slice cimport PySlice_Check
 
 cdef extern from "Python.h":
     Py_ssize_t PY_SSIZE_T_MAX
@@ -30,14 +29,15 @@ cdef class BlockPlacement:
     cdef bint _has_slice, _has_array, _is_known_slice_like
 
     def __init__(self, val):
-        cdef slice slc
+        cdef:
+            slice slc
 
         self._as_slice = None
         self._as_array = None
         self._has_slice = False
         self._has_array = False
 
-        if PySlice_Check(val):
+        if isinstance(val, slice):
             slc = slice_canonize(val)
 
             if slc.start != slc.stop:
@@ -55,7 +55,8 @@ cdef class BlockPlacement:
             self._has_array = True
 
     def __str__(self):
-        cdef slice s = self._ensure_has_slice()
+        cdef:
+            slice s = self._ensure_has_slice()
         if s is not None:
             v = self._as_slice
         else:
@@ -66,15 +67,17 @@ cdef class BlockPlacement:
     __repr__ = __str__
 
     def __len__(self):
-        cdef slice s = self._ensure_has_slice()
+        cdef:
+            slice s = self._ensure_has_slice()
         if s is not None:
             return slice_len(s)
         else:
             return len(self._as_array)
 
     def __iter__(self):
-        cdef slice s = self._ensure_has_slice()
-        cdef Py_ssize_t start, stop, step, _
+        cdef:
+            slice s = self._ensure_has_slice()
+            Py_ssize_t start, stop, step, _
         if s is not None:
             start, stop, step, _ = slice_get_indices_ex(s)
             return iter(range(start, stop, step))
@@ -83,7 +86,8 @@ cdef class BlockPlacement:
 
     @property
     def as_slice(self):
-        cdef slice s = self._ensure_has_slice()
+        cdef:
+            slice s = self._ensure_has_slice()
         if s is None:
             raise TypeError('Not slice-like')
         else:
@@ -91,7 +95,8 @@ cdef class BlockPlacement:
 
     @property
     def indexer(self):
-        cdef slice s = self._ensure_has_slice()
+        cdef:
+            slice s = self._ensure_has_slice()
         if s is not None:
             return s
         else:
@@ -103,7 +108,8 @@ cdef class BlockPlacement:
 
     @property
     def as_array(self):
-        cdef Py_ssize_t start, stop, end, _
+        cdef:
+            Py_ssize_t start, stop, end, _
         if not self._has_array:
             start, stop, step, _ = slice_get_indices_ex(self._as_slice)
             self._as_array = np.arange(start, stop, step,
@@ -113,17 +119,19 @@ cdef class BlockPlacement:
 
     @property
     def is_slice_like(self):
-        cdef slice s = self._ensure_has_slice()
+        cdef:
+            slice s = self._ensure_has_slice()
         return s is not None
 
     def __getitem__(self, loc):
-        cdef slice s = self._ensure_has_slice()
+        cdef:
+            slice s = self._ensure_has_slice()
         if s is not None:
             val = slice_getitem(s, loc)
         else:
             val = self._as_array[loc]
 
-        if not PySlice_Check(val) and val.ndim == 0:
+        if not isinstance(val, slice) and val.ndim == 0:
             return val
 
         return BlockPlacement(val)
@@ -139,8 +147,9 @@ cdef class BlockPlacement:
                                              [o.as_array for o in others]))
 
     cdef iadd(self, other):
-        cdef slice s = self._ensure_has_slice()
-        cdef Py_ssize_t other_int, start, stop, step, l
+        cdef:
+            slice s = self._ensure_has_slice()
+            Py_ssize_t other_int, start, stop, step, l
 
         if isinstance(other, int) and s is not None:
             other_int = <Py_ssize_t>other
@@ -184,7 +193,7 @@ cdef class BlockPlacement:
         return self._as_slice
 
 
-cdef slice_canonize(slice s):
+cdef slice slice_canonize(slice s):
     """
     Convert slice to canonical bounded form.
     """
@@ -282,7 +291,7 @@ def slice_getitem(slice slc not None, ind):
 
     s_start, s_stop, s_step, s_len = slice_get_indices_ex(slc)
 
-    if PySlice_Check(ind):
+    if isinstance(ind, slice):
         ind_start, ind_stop, ind_step, ind_len = slice_get_indices_ex(ind,
                                                                       s_len)
 
diff --git a/pandas/_libs/interval.pyx b/pandas/_libs/interval.pyx
index d8e2e8eb4b4ea..82261094022fb 100644
--- a/pandas/_libs/interval.pyx
+++ b/pandas/_libs/interval.pyx
@@ -271,7 +271,7 @@ cdef class Interval(IntervalMixin):
         return ((self.left < key if self.open_left else self.left <= key) and
                 (key < self.right if self.open_right else key <= self.right))
 
-    def __richcmp__(self, other, int op):
+    def __richcmp__(self, other, op: int):
         if hasattr(other, 'ndim'):
             # let numpy (or IntervalIndex) handle vectorization
             return NotImplemented
diff --git a/pandas/_libs/lib.pyx b/pandas/_libs/lib.pyx
index 6b425d7022ecd..0b9793a6ef97a 100644
--- a/pandas/_libs/lib.pyx
+++ b/pandas/_libs/lib.pyx
@@ -2,14 +2,10 @@
 from decimal import Decimal
 import sys
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 from cpython cimport (Py_INCREF, PyTuple_SET_ITEM,
-                      PyList_Check,
-                      PyString_Check,
-                      PyBytes_Check,
-                      PyUnicode_Check,
                       PyTuple_New,
                       Py_EQ,
                       PyObject_RichCompareBool)
@@ -91,13 +87,14 @@ def values_from_object(object obj):
 
 @cython.wraparound(False)
 @cython.boundscheck(False)
-def memory_usage_of_objects(object[:] arr):
+def memory_usage_of_objects(arr: object[:]) -> int64_t:
     """ return the memory usage of an object array in bytes,
     does not include the actual bytes of the pointers """
-    cdef:
-        Py_ssize_t i, n
-        int64_t size = 0
+    i: Py_ssize_t
+    n: Py_ssize_t
+    size: int64_t
 
+    size = 0
     n = len(arr)
     for i in range(n):
         size += arr[i].__sizeof__()
@@ -127,7 +124,7 @@ def is_scalar(val: object) -> bint:
 
     return (cnp.PyArray_IsAnyScalar(val)
             # As of numpy-1.9, PyArray_IsAnyScalar misses bytearrays on Py3.
-            or PyBytes_Check(val)
+            or isinstance(val, bytes)
             # We differ from numpy (as of 1.10), which claims that None is
             # not scalar in np.isscalar().
             or val is None
@@ -140,7 +137,7 @@ def is_scalar(val: object) -> bint:
             or util.is_offset_object(val))
 
 
-def item_from_zerodim(object val):
+def item_from_zerodim(val: object) -> object:
     """
     If the value is a zerodim array, return the item it contains.
 
@@ -359,7 +356,7 @@ def get_reverse_indexer(ndarray[int64_t] indexer, Py_ssize_t length):
     return rev_indexer
 
 
-def has_infs_f4(ndarray[float32_t] arr):
+def has_infs_f4(ndarray[float32_t] arr) -> bint:
     cdef:
         Py_ssize_t i, n = len(arr)
         float32_t inf, neginf, val
@@ -374,7 +371,7 @@ def has_infs_f4(ndarray[float32_t] arr):
     return False
 
 
-def has_infs_f8(ndarray[float64_t] arr):
+def has_infs_f8(ndarray[float64_t] arr) -> bint:
     cdef:
         Py_ssize_t i, n = len(arr)
         float64_t inf, neginf, val
@@ -530,7 +527,8 @@ def clean_index_list(list obj):
 
     for i in range(n):
         v = obj[i]
-        if not (PyList_Check(v) or util.is_array(v) or hasattr(v, '_data')):
+        if not (isinstance(v, list) or
+                util.is_array(v) or hasattr(v, '_data')):
             all_arrays = 0
             break
 
@@ -1120,7 +1118,7 @@ def infer_dtype(object value, bint skipna=False):
                              .format(typ=type(value)))
 
     else:
-        if not PyList_Check(value):
+        if not isinstance(value, list):
             value = list(value)
         from pandas.core.dtypes.cast import (
             construct_1d_object_array_from_listlike)
@@ -1209,15 +1207,15 @@ def infer_dtype(object value, bint skipna=False):
         if is_bool_array(values, skipna=skipna):
             return 'boolean'
 
-    elif PyString_Check(val):
+    elif isinstance(val, str):
         if is_string_array(values, skipna=skipna):
             return 'string'
 
-    elif PyUnicode_Check(val):
+    elif isinstance(val, unicode):
         if is_unicode_array(values, skipna=skipna):
             return 'unicode'
 
-    elif PyBytes_Check(val):
+    elif isinstance(val, bytes):
         if is_bytes_array(values, skipna=skipna):
             return 'bytes'
 
@@ -1474,7 +1472,7 @@ cpdef bint is_float_array(ndarray values):
 
 cdef class StringValidator(Validator):
     cdef inline bint is_value_typed(self, object value) except -1:
-        return PyString_Check(value)
+        return isinstance(value, str)
 
     cdef inline bint is_array_typed(self) except -1:
         return issubclass(self.dtype.type, np.str_)
@@ -1490,7 +1488,7 @@ cpdef bint is_string_array(ndarray values, bint skipna=False):
 
 cdef class UnicodeValidator(Validator):
     cdef inline bint is_value_typed(self, object value) except -1:
-        return PyUnicode_Check(value)
+        return isinstance(value, unicode)
 
     cdef inline bint is_array_typed(self) except -1:
         return issubclass(self.dtype.type, np.unicode_)
@@ -1506,7 +1504,7 @@ cdef bint is_unicode_array(ndarray values, bint skipna=False):
 
 cdef class BytesValidator(Validator):
     cdef inline bint is_value_typed(self, object value) except -1:
-        return PyBytes_Check(value)
+        return isinstance(value, bytes)
 
     cdef inline bint is_array_typed(self) except -1:
         return issubclass(self.dtype.type, np.bytes_)
diff --git a/pandas/_libs/missing.pyx b/pandas/_libs/missing.pyx
index c787cc61e8773..2590a30c57f33 100644
--- a/pandas/_libs/missing.pyx
+++ b/pandas/_libs/missing.pyx
@@ -1,9 +1,7 @@
 # -*- coding: utf-8 -*-
 
-from cpython cimport PyFloat_Check, PyComplex_Check
-
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 import numpy as np
 cimport numpy as cnp
@@ -23,8 +21,9 @@ cdef int64_t NPY_NAT = util.get_nat()
 
 cdef inline bint _check_all_nulls(object val):
     """ utility to check if a value is any type of null """
-    cdef bint res
-    if PyFloat_Check(val) or PyComplex_Check(val):
+    res: bint
+
+    if isinstance(val, (float, complex)):
         res = val != val
     elif val is NaT:
         res = 1
@@ -117,7 +116,7 @@ cpdef bint checknull_old(object val):
 
 cdef inline bint _check_none_nan_inf_neginf(object val):
     try:
-        return val is None or (PyFloat_Check(val) and
+        return val is None or (isinstance(val, float) and
                                (val != val or val == INF or val == NEGINF))
     except ValueError:
         return False
diff --git a/pandas/_libs/ops.pyx b/pandas/_libs/ops.pyx
index a194f1588e231..e21bce177b38b 100644
--- a/pandas/_libs/ops.pyx
+++ b/pandas/_libs/ops.pyx
@@ -1,12 +1,11 @@
 # -*- coding: utf-8 -*-
 import operator
 
-from cpython cimport (PyFloat_Check, PyBool_Check,
-                      PyObject_RichCompareBool,
+from cpython cimport (PyObject_RichCompareBool,
                       Py_EQ, Py_NE, Py_LT, Py_LE, Py_GT, Py_GE)
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 import numpy as np
 from numpy cimport ndarray, uint8_t, import_array
@@ -272,7 +271,7 @@ def maybe_convert_bool(ndarray[object] arr,
     for i in range(n):
         val = arr[i]
 
-        if PyBool_Check(val):
+        if isinstance(val, bool):
             if val is True:
                 result[i] = 1
             else:
@@ -281,7 +280,7 @@ def maybe_convert_bool(ndarray[object] arr,
             result[i] = 1
         elif val in false_vals:
             result[i] = 0
-        elif PyFloat_Check(val):
+        elif isinstance(val, float):
             result[i] = UINT8_MAX
             na_count += 1
         else:
diff --git a/pandas/_libs/parsers.pyx b/pandas/_libs/parsers.pyx
index 91faed678192f..e3df391c5c45d 100644
--- a/pandas/_libs/parsers.pyx
+++ b/pandas/_libs/parsers.pyx
@@ -10,12 +10,12 @@ from csv import QUOTE_MINIMAL, QUOTE_NONNUMERIC, QUOTE_NONE
 from libc.stdlib cimport free
 from libc.string cimport strncpy, strlen, strcasecmp
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 from cpython cimport (PyObject, PyBytes_FromString,
-                      PyBytes_AsString, PyBytes_Check,
-                      PyUnicode_Check, PyUnicode_AsUTF8String,
+                      PyBytes_AsString,
+                      PyUnicode_AsUTF8String,
                       PyErr_Occurred, PyErr_Fetch)
 from cpython.ref cimport Py_XDECREF
 
@@ -1341,9 +1341,9 @@ cdef object _false_values = [b'False', b'FALSE', b'false']
 def _ensure_encoded(list lst):
     cdef list result = []
     for x in lst:
-        if PyUnicode_Check(x):
+        if isinstance(x, unicode):
             x = PyUnicode_AsUTF8String(x)
-        elif not PyBytes_Check(x):
+        elif not isinstance(x, bytes):
             x = asbytes(x)
 
         result.append(x)
@@ -2046,7 +2046,7 @@ cdef kh_str_t* kset_from_list(list values) except NULL:
         val = values[i]
 
         # None creeps in sometimes, which isn't possible here
-        if not PyBytes_Check(val):
+        if not isinstance(val, bytes):
             raise ValueError('Must be all encoded bytes')
 
         k = kh_put_str(table, PyBytes_AsString(val), &ret)
diff --git a/pandas/_libs/properties.pyx b/pandas/_libs/properties.pyx
index 0f2900619fdb6..6e4c0c62b0dd8 100644
--- a/pandas/_libs/properties.pyx
+++ b/pandas/_libs/properties.pyx
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from cython cimport Py_ssize_t
+from cython import Py_ssize_t
 
 from cpython cimport (
     PyDict_Contains, PyDict_GetItem, PyDict_SetItem)
diff --git a/pandas/_libs/reduction.pyx b/pandas/_libs/reduction.pyx
index d87a590730fd6..681ea2c6295f2 100644
--- a/pandas/_libs/reduction.pyx
+++ b/pandas/_libs/reduction.pyx
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 from distutils.version import LooseVersion
 
-from cython cimport Py_ssize_t
+from cython import Py_ssize_t
 from cpython cimport Py_INCREF
 
 from libc.stdlib cimport malloc, free
diff --git a/pandas/_libs/sparse.pyx b/pandas/_libs/sparse.pyx
index 7f5990ce5d65c..2993114a668bb 100644
--- a/pandas/_libs/sparse.pyx
+++ b/pandas/_libs/sparse.pyx
@@ -2,7 +2,7 @@
 import operator
 import sys
 
-cimport cython
+import cython
 
 import numpy as np
 cimport numpy as cnp
diff --git a/pandas/_libs/testing.pyx b/pandas/_libs/testing.pyx
index ab7f3c3de2131..10f68187938c0 100644
--- a/pandas/_libs/testing.pyx
+++ b/pandas/_libs/testing.pyx
@@ -22,24 +22,30 @@ cdef NUMERIC_TYPES = (
     np.float64,
 )
 
+
 cdef bint is_comparable_as_number(obj):
     return isinstance(obj, NUMERIC_TYPES)
 
+
 cdef bint isiterable(obj):
     return hasattr(obj, '__iter__')
 
+
 cdef bint has_length(obj):
     return hasattr(obj, '__len__')
 
+
 cdef bint is_dictlike(obj):
     return hasattr(obj, 'keys') and hasattr(obj, '__getitem__')
 
+
 cdef bint decimal_almost_equal(double desired, double actual, int decimal):
     # Code from
     # http://docs.scipy.org/doc/numpy/reference/generated
     # /numpy.testing.assert_almost_equal.html
     return abs(desired - actual) < (0.5 * 10.0 ** -decimal)
 
+
 cpdef assert_dict_equal(a, b, bint compare_keys=True):
     assert is_dictlike(a) and is_dictlike(b), (
         "Cannot compare dict objects, one or both is not dict-like"
@@ -56,6 +62,7 @@ cpdef assert_dict_equal(a, b, bint compare_keys=True):
 
     return True
 
+
 cpdef assert_almost_equal(a, b,
                           check_less_precise=False,
                           bint check_dtype=True,
diff --git a/pandas/_libs/tslib.pyx b/pandas/_libs/tslib.pyx
index 93fae695d51fd..16fea0615f199 100644
--- a/pandas/_libs/tslib.pyx
+++ b/pandas/_libs/tslib.pyx
@@ -1,7 +1,5 @@
 # -*- coding: utf-8 -*-
-from cython cimport Py_ssize_t
-
-from cpython cimport PyFloat_Check, PyUnicode_Check
+from cython import Py_ssize_t
 
 from cpython.datetime cimport (PyDateTime_Check, PyDate_Check,
                                PyDateTime_CheckExact,
@@ -601,7 +599,7 @@ cpdef array_to_datetime(ndarray[object] values, errors='raise',
                 if len(val) == 0 or val in nat_strings:
                     iresult[i] = NPY_NAT
                     continue
-                if PyUnicode_Check(val) and PY2:
+                if isinstance(val, unicode) and PY2:
                     val = val.encode('utf-8')
 
                 try:
@@ -740,7 +738,7 @@ cpdef array_to_datetime(ndarray[object] values, errors='raise',
 
             # set as nan except if its a NaT
             if checknull_with_nat(val):
-                if PyFloat_Check(val):
+                if isinstance(val, float):
                     oresult[i] = np.nan
                 else:
                     oresult[i] = NaT
diff --git a/pandas/_libs/tslibs/ccalendar.pyx b/pandas/_libs/tslibs/ccalendar.pyx
index ec54c023290b3..7d58b43e5d460 100644
--- a/pandas/_libs/tslibs/ccalendar.pyx
+++ b/pandas/_libs/tslibs/ccalendar.pyx
@@ -4,8 +4,8 @@
 Cython implementations of functions resembling the stdlib calendar module
 """
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 from numpy cimport int64_t, int32_t
 
diff --git a/pandas/_libs/tslibs/conversion.pyx b/pandas/_libs/tslibs/conversion.pyx
index fe664cf03b0b9..d7eef546befbd 100644
--- a/pandas/_libs/tslibs/conversion.pyx
+++ b/pandas/_libs/tslibs/conversion.pyx
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 import numpy as np
 cimport numpy as cnp
diff --git a/pandas/_libs/tslibs/fields.pyx b/pandas/_libs/tslibs/fields.pyx
index 9cbad8acabff1..684344ceb9002 100644
--- a/pandas/_libs/tslibs/fields.pyx
+++ b/pandas/_libs/tslibs/fields.pyx
@@ -4,8 +4,8 @@ Functions for accessing attributes of Timestamp/datetime64/datetime-like
 objects and arrays
 """
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 import numpy as np
 cimport numpy as cnp
diff --git a/pandas/_libs/tslibs/frequencies.pyx b/pandas/_libs/tslibs/frequencies.pyx
index 70a3f3f410636..c555fce9dd007 100644
--- a/pandas/_libs/tslibs/frequencies.pyx
+++ b/pandas/_libs/tslibs/frequencies.pyx
@@ -321,7 +321,7 @@ cpdef object get_freq(object freq):
 # ----------------------------------------------------------------------
 # Frequency comparison
 
-cpdef bint is_subperiod(source, target):
+def is_subperiod(source, target) -> bint:
     """
     Returns True if downsampling is possible between source and target
     frequencies
@@ -374,7 +374,7 @@ cpdef bint is_subperiod(source, target):
         return source in {'N'}
 
 
-cpdef bint is_superperiod(source, target):
+def is_superperiod(source, target) -> bint:
     """
     Returns True if upsampling is possible between source and target
     frequencies
diff --git a/pandas/_libs/tslibs/nattype.pyx b/pandas/_libs/tslibs/nattype.pyx
index 08d9128ff660c..fd8486f690745 100644
--- a/pandas/_libs/tslibs/nattype.pyx
+++ b/pandas/_libs/tslibs/nattype.pyx
@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 
 from cpython cimport (
-    PyFloat_Check, PyComplex_Check,
     PyObject_RichCompare,
     Py_GT, Py_GE, Py_EQ, Py_NE, Py_LT, Py_LE)
 
diff --git a/pandas/_libs/tslibs/np_datetime.pyx b/pandas/_libs/tslibs/np_datetime.pyx
index f0aa6389fba56..e0ecfc24804a9 100644
--- a/pandas/_libs/tslibs/np_datetime.pyx
+++ b/pandas/_libs/tslibs/np_datetime.pyx
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 from cpython cimport (Py_EQ, Py_NE, Py_GE, Py_GT, Py_LT, Py_LE,
-                      PyUnicode_Check, PyUnicode_AsASCIIString)
+                      PyUnicode_AsASCIIString)
 
 from cpython.datetime cimport (datetime, date,
                                PyDateTime_IMPORT,
@@ -175,7 +175,7 @@ cdef inline int _string_to_dts(object val, npy_datetimestruct* dts,
         int result
         char *tmp
 
-    if PyUnicode_Check(val):
+    if isinstance(val, unicode):
         val = PyUnicode_AsASCIIString(val)
 
     tmp = val
diff --git a/pandas/_libs/tslibs/offsets.pyx b/pandas/_libs/tslibs/offsets.pyx
index 8c53fabffdbeb..4d611f89bca9c 100644
--- a/pandas/_libs/tslibs/offsets.pyx
+++ b/pandas/_libs/tslibs/offsets.pyx
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 import time
 from cpython.datetime cimport (PyDateTime_IMPORT,
diff --git a/pandas/_libs/tslibs/parsing.pyx b/pandas/_libs/tslibs/parsing.pyx
index 6ee6c4b9d9026..3887957aeefd4 100644
--- a/pandas/_libs/tslibs/parsing.pyx
+++ b/pandas/_libs/tslibs/parsing.pyx
@@ -537,7 +537,7 @@ except (ImportError, AttributeError):
     pass
 
 
-def _format_is_iso(f):
+def _format_is_iso(f) -> bint:
     """
     Does format match the iso8601 set that can be handled by the C parser?
     Generally of form YYYY-MM-DDTHH:MM:SS - date separator can be different
diff --git a/pandas/_libs/tslibs/period.pyx b/pandas/_libs/tslibs/period.pyx
index f68b6d8fdef57..43dc415bfd464 100644
--- a/pandas/_libs/tslibs/period.pyx
+++ b/pandas/_libs/tslibs/period.pyx
@@ -2397,7 +2397,6 @@ class Period(_Period):
         # ('T', 5) but may be passed in as a string like '5T'
 
         # ordinal is the period offset from the gregorian proleptic epoch
-
         cdef _Period self
 
         if freq is not None:
@@ -2495,7 +2494,7 @@ cdef int64_t _ordinal_from_fields(int year, int month, quarter, int day,
                           minute, second, 0, 0, base)
 
 
-def quarter_to_myear(int year, int quarter, freq):
+def quarter_to_myear(year: int, quarter: int, freq):
     """
     A quarterly frequency defines a "year" which may not coincide with
     the calendar-year.  Find the calendar-year and calendar-month associated
diff --git a/pandas/_libs/tslibs/resolution.pyx b/pandas/_libs/tslibs/resolution.pyx
index 4e3350395400c..4acffdea78f55 100644
--- a/pandas/_libs/tslibs/resolution.pyx
+++ b/pandas/_libs/tslibs/resolution.pyx
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from cython cimport Py_ssize_t
+from cython import Py_ssize_t
 
 import numpy as np
 from numpy cimport ndarray, int64_t, int32_t
diff --git a/pandas/_libs/tslibs/strptime.pyx b/pandas/_libs/tslibs/strptime.pyx
index d472320cfdb12..46a1145009857 100644
--- a/pandas/_libs/tslibs/strptime.pyx
+++ b/pandas/_libs/tslibs/strptime.pyx
@@ -20,7 +20,7 @@ except:
         except:
             from _dummy_thread import allocate_lock as _thread_allocate_lock
 
-from cython cimport Py_ssize_t
+from cython import Py_ssize_t
 
 
 import pytz
diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index b84c1a753215a..9b13ef5982396 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -6,9 +6,9 @@ import warnings
 import sys
 cdef bint PY3 = (sys.version_info[0] >= 3)
 
-from cython cimport Py_ssize_t
+from cython import Py_ssize_t
 
-from cpython cimport PyUnicode_Check, Py_NE, Py_EQ, PyObject_RichCompare
+from cpython cimport Py_NE, Py_EQ, PyObject_RichCompare
 
 import numpy as np
 cimport numpy as cnp
@@ -281,7 +281,7 @@ cpdef inline int64_t cast_from_unit(object ts, object unit) except? -1:
 
 cdef inline _decode_if_necessary(object ts):
     # decode ts if necessary
-    if not PyUnicode_Check(ts) and not PY3:
+    if not isinstance(ts, unicode) and not PY3:
         ts = str(ts).decode('utf-8')
 
     return ts
diff --git a/pandas/_libs/tslibs/timezones.pyx b/pandas/_libs/tslibs/timezones.pyx
index 36ec499c7335c..b7e4de81da35c 100644
--- a/pandas/_libs/tslibs/timezones.pyx
+++ b/pandas/_libs/tslibs/timezones.pyx
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-from cython cimport Py_ssize_t
+from cython import Py_ssize_t
 
 # dateutil compat
 from dateutil.tz import (
diff --git a/pandas/_libs/window.pyx b/pandas/_libs/window.pyx
index b25fb47065fdd..d4b61b8611b68 100644
--- a/pandas/_libs/window.pyx
+++ b/pandas/_libs/window.pyx
@@ -1,8 +1,8 @@
 # -*- coding: utf-8 -*-
 # cython: boundscheck=False, wraparound=False, cdivision=True
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 from libcpp.deque cimport deque
 
 from libc.stdlib cimport malloc, free
diff --git a/pandas/_libs/writers.pyx b/pandas/_libs/writers.pyx
index 8e55ffad8d231..9af12cbec1e9c 100644
--- a/pandas/_libs/writers.pyx
+++ b/pandas/_libs/writers.pyx
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
-cimport cython
-from cython cimport Py_ssize_t
+import cython
+from cython import Py_ssize_t
 
 from cpython cimport PyBytes_GET_SIZE, PyUnicode_GET_SIZE
 
@@ -36,9 +36,10 @@ def write_csv_rows(list data, ndarray data_index,
     cols : ndarray
     writer : object
     """
-    cdef int N, j, i, ncols
-    cdef list rows
-    cdef object val
+    cdef:
+        int N, j, i, ncols
+        list rows
+        object val
 
     # In crude testing, N>100 yields little marginal improvement
     N = 100
@@ -157,8 +158,9 @@ def string_array_replace_from_nan_rep(
     Replace the values in the array with 'replacement' if
     they are 'nan_rep'. Return the same array.
     """
+    cdef:
+        int length = arr.shape[0], i = 0
 
-    cdef int length = arr.shape[0], i = 0
     if replace is None:
         replace = np.nan
 
diff --git a/setup.cfg b/setup.cfg
index c4e3243d824e5..5fc0236066b93 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -40,3 +40,33 @@ markers =
     high_memory: mark a test as a high-memory only
 doctest_optionflags = NORMALIZE_WHITESPACE IGNORE_EXCEPTION_DETAIL
 addopts = --strict-data-files
+
+
+[coverage:run]
+branch = False
+omit = */tests/*
+plugins = Cython.Coverage
+
+[coverage:report]
+ignore_errors = False
+show_missing = True
+# Regexes for lines to exclude from consideration
+exclude_lines =
+    # Have to re-enable the standard pragma
+    pragma: no cover
+
+    # Don't complain about missing debug-only code:
+    def __repr__
+    if self\.debug
+
+    # Don't complain if tests don't hit defensive assertion code:
+    raise AssertionError
+    raise NotImplementedError
+    AbstractMethodError
+
+    # Don't complain if non-runnable code isn't run:
+    if 0:
+    if __name__ == .__main__.:
+
+[coverage:html]
+directory = coverage_html_report