diff --git a/doc/modules/validation.rst b/doc/modules/validation.rst
index 1fdc70843..ea784bfcc 100644
--- a/doc/modules/validation.rst
+++ b/doc/modules/validation.rst
@@ -11,7 +11,7 @@
    :toctree: generated/utils
    :template: function.rst
 
-   utils.check_diagrams
-   utils.check_point_clouds
    utils.check_collection
+   utils.check_point_clouds
+   utils.check_diagrams
    utils.validate_params
diff --git a/gtda/time_series/tests/test_features.py b/gtda/time_series/tests/test_features.py
index 84aa5b6b1..90a7087b9 100644
--- a/gtda/time_series/tests/test_features.py
+++ b/gtda/time_series/tests/test_features.py
@@ -3,7 +3,7 @@
 
 import numpy as np
 from numpy.testing import assert_almost_equal
-from gtda.time_series.features import PermutationEntropy
+from gtda.time_series import PermutationEntropy
 from itertools import product
 
 X = np.ones((10, 200, 3))  # 10 samples, of 200 points embedded in a 3d space
diff --git a/gtda/time_series/tests/test_target.py b/gtda/time_series/tests/test_target.py
index d41d13db6..9d03c4fb8 100644
--- a/gtda/time_series/tests/test_target.py
+++ b/gtda/time_series/tests/test_target.py
@@ -5,7 +5,7 @@
 from numpy.testing import assert_almost_equal
 import pytest
 
-from gtda.time_series.target import Labeller
+from gtda.time_series import Labeller
 
 signal = np.asarray([np.sin(x / 2) + 2 for x in range(0, 20)])
 X = np.tile(np.arange(10), reps=2)
diff --git a/gtda/utils/__init__.py b/gtda/utils/__init__.py
index 919720e5a..9d5aca644 100644
--- a/gtda/utils/__init__.py
+++ b/gtda/utils/__init__.py
@@ -1,11 +1,13 @@
-"""The module :mod:`gtda.utils` implements hyperparameter and input
-validation functions."""
+"""The module :mod:`gtda.utils` implements hyperparameter and input validation
+functions."""
 
-from .validation import check_diagrams, check_point_clouds, validate_params
+from .validation import check_collection, check_point_clouds, check_diagrams, \
+    validate_params
 
 
 __all__ = [
-    'check_diagrams',
-    'check_point_clouds',
-    'validate_params'
-]
+    "check_collection",
+    "check_point_clouds",
+    "check_diagrams",
+    "validate_params"
+    ]
diff --git a/gtda/utils/tests/test_validation.py b/gtda/utils/tests/test_validation.py
index a0abe59e9..8d704c222 100644
--- a/gtda/utils/tests/test_validation.py
+++ b/gtda/utils/tests/test_validation.py
@@ -5,8 +5,8 @@
 import pytest
 from sklearn.exceptions import DataDimensionalityWarning
 
-from gtda.utils.validation import check_diagrams, validate_params, \
-    check_point_clouds, check_collection
+from gtda.utils import check_collection, check_point_clouds, check_diagrams, \
+    validate_params
 
 
 # Testing for validate_params