diff --git a/src/sage/algebras/hecke_algebras/ariki_koike_algebra.py b/src/sage/algebras/hecke_algebras/ariki_koike_algebra.py
index b78b7691e7b..2e4ddb6a4bd 100644
--- a/src/sage/algebras/hecke_algebras/ariki_koike_algebra.py
+++ b/src/sage/algebras/hecke_algebras/ariki_koike_algebra.py
@@ -1126,7 +1126,7 @@ def inverse_T(self, i):
             return self._from_dict({m: ~self._q, self.one_basis(): c})
 
         class Element(CombinatorialFreeModule.Element):
-            def inverse(self):
+            def __invert__(self):
                 r"""
                 Return the inverse if ``self`` is a basis element.
 
@@ -1135,7 +1135,7 @@ def inverse(self):
                     sage: LT = algebras.ArikiKoike(3, 4).LT()
                     sage: t = LT.T(1) * LT.T(2) * LT.T(3); t
                     T[1,2,3]
-                    sage: t.inverse()
+                    sage: t.inverse()   # indirect doctest
                     (q^-3-3*q^-2+3*q^-1-1) + (q^-3-2*q^-2+q^-1)*T[3]
                      + (q^-3-2*q^-2+q^-1)*T[2] + (q^-3-q^-2)*T[3,2]
                      + (q^-3-2*q^-2+q^-1)*T[1] + (q^-3-q^-2)*T[1,3]
@@ -1149,8 +1149,6 @@ def inverse(self):
                 H = self.parent()
                 return ~self[l,w] * H.prod(H.inverse_T(i) for i in reversed(w.reduced_word()))
 
-            __invert__ = inverse
-
     class T(_Basis):
         r"""
         The basis of the Ariki-Koike algebra given by monomials of the
diff --git a/src/sage/algebras/iwahori_hecke_algebra.py b/src/sage/algebras/iwahori_hecke_algebra.py
index ae50b39a3e0..b779269b2f8 100644
--- a/src/sage/algebras/iwahori_hecke_algebra.py
+++ b/src/sage/algebras/iwahori_hecke_algebra.py
@@ -1727,7 +1727,7 @@ class Element(CombinatorialFreeModule.Element):
                 sage: T1.parent()
                 Iwahori-Hecke algebra of type A2 in 1,-1 over Integer Ring in the T-basis
             """
-            def inverse(self):
+            def __invert__(self):
                 r"""
                 Return the inverse if ``self`` is a basis element.
 
@@ -1741,7 +1741,7 @@ def inverse(self):
                     sage: R.<q> = LaurentPolynomialRing(QQ)
                     sage: H = IwahoriHeckeAlgebra("A2", q).T()
                     sage: [T1,T2] = H.algebra_generators()
-                    sage: x = (T1*T2).inverse(); x
+                    sage: x = (T1*T2).inverse(); x   # indirect doctest
                     (q^-2)*T[2,1] + (q^-2-q^-1)*T[1] + (q^-2-q^-1)*T[2] + (q^-2-2*q^-1+1)
                     sage: x*T1*T2
                     1
@@ -1766,8 +1766,6 @@ def inverse(self):
 
                 return H.prod(H.inverse_generator(i) for i in reversed(w.reduced_word()))
 
-            __invert__ = inverse
-
     standard = T
 
     class _KLHeckeBasis(_Basis):
diff --git a/src/sage/algebras/yokonuma_hecke_algebra.py b/src/sage/algebras/yokonuma_hecke_algebra.py
index dde7772e227..a8c74e25f0b 100644
--- a/src/sage/algebras/yokonuma_hecke_algebra.py
+++ b/src/sage/algebras/yokonuma_hecke_algebra.py
@@ -454,7 +454,7 @@ def inverse_g(self, i):
         return self.g(i) + (~self._q + self._q) * self.e(i)
 
     class Element(CombinatorialFreeModule.Element):
-        def inverse(self):
+        def __invert__(self):
             r"""
             Return the inverse if ``self`` is a basis element.
 
@@ -463,7 +463,7 @@ def inverse(self):
                 sage: Y = algebras.YokonumaHecke(3, 3)
                 sage: t = prod(Y.t()); t
                 t1*t2*t3
-                sage: ~t
+                sage: t.inverse()   # indirect doctest
                 t1^2*t2^2*t3^2
                 sage: [3*~(t*g) for g in Y.g()]
                 [(q^-1+q)*t2*t3^2 + (q^-1+q)*t1*t3^2
@@ -494,6 +494,3 @@ def inverse(self):
             c = ~self.coefficients()[0]
             telt = H.monomial( (tuple((H._d - e) % H._d for e in t), H._Pn.one()) )
             return c * telt * H.prod(H.inverse_g(i) for i in reversed(w.reduced_word()))
-
-        __invert__ = inverse
-
diff --git a/src/sage/categories/complex_reflection_or_generalized_coxeter_groups.py b/src/sage/categories/complex_reflection_or_generalized_coxeter_groups.py
index 720d0097632..daa36275cf9 100644
--- a/src/sage/categories/complex_reflection_or_generalized_coxeter_groups.py
+++ b/src/sage/categories/complex_reflection_or_generalized_coxeter_groups.py
@@ -1141,7 +1141,7 @@ def _mul_(self, other):
             """
             return self.apply_simple_reflections(other.reduced_word())
 
-        def inverse(self):
+        def __invert__(self):
             """
             Return the inverse of ``self``.
 
@@ -1149,7 +1149,7 @@ def inverse(self):
 
                 sage: W = WeylGroup(['B',7])
                 sage: w = W.an_element()
-                sage: u = w.inverse()
+                sage: u = w.inverse()  # indirect doctest
                 sage: u == ~w
                 True
                 sage: u * w == w * u
@@ -1165,8 +1165,6 @@ def inverse(self):
             """
             return self.parent().one().apply_simple_reflections(self.reduced_word_reverse_iterator())
 
-        __invert__ = inverse
-
         def apply_conjugation_by_simple_reflection(self, i):
             r"""
             Conjugate ``self`` by the ``i``-th simple reflection.
diff --git a/src/sage/categories/monoids.py b/src/sage/categories/monoids.py
index 42b55b8dda4..d598a6cecb3 100644
--- a/src/sage/categories/monoids.py
+++ b/src/sage/categories/monoids.py
@@ -313,6 +313,36 @@ def powers(self, n):
                 l.append(x)
             return l
 
+        def __invert__(self):
+            r"""
+            Return the inverse of ``self``.
+
+            The default implementation is to divide ``self.one()``.
+
+            EXAMPLES::
+
+                sage: A = Matrix([[1, 0], [1, 1]])
+                sage: ~A
+                [ 1 0]
+                [-1 1]
+            """
+            return self.parent().one()._div_(self)
+
+        def inverse(self):
+            """
+            Return the inverse of ``self``.
+
+            This an alias for inversion, defined in ``__invert__``.
+
+            Element classes should implement ``__invert__`` only.
+
+            EXAMPLES::
+
+                sage: AA(sqrt(~2)).inverse()
+                1.414213562373095?
+            """
+            return self.__invert__()
+
     class Commutative(CategoryWithAxiom):
         r"""
         Category of commutative (abelian) monoids.
diff --git a/src/sage/combinat/affine_permutation.py b/src/sage/combinat/affine_permutation.py
index 5da8030f454..b519553a777 100644
--- a/src/sage/combinat/affine_permutation.py
+++ b/src/sage/combinat/affine_permutation.py
@@ -159,21 +159,19 @@ def __mul__(self, q):
         return self.__rmul__(q)
 
     @cached_method
-    def inverse(self):
+    def __invert__(self):
         r"""
         Return the inverse affine permutation.
 
         EXAMPLES::
 
             sage: p = AffinePermutationGroup(['A',7,1])([3, -1, 0, 6, 5, 4, 10, 9])
-            sage: p.inverse()
+            sage: p.inverse()  # indirect doctest
             Type A affine permutation with window [0, -1, 1, 6, 5, 4, 10, 11]
         """
-        inv = [self.position(i) for i in range(1,len(self)+1)]
+        inv = [self.position(i) for i in range(1, len(self) + 1)]
         return type(self)(self.parent(), inv, check=False)
 
-    __invert__=inverse
-
     def apply_simple_reflection(self, i, side='right'):
         r"""
         Apply a simple reflection.
@@ -853,8 +851,8 @@ def to_lehmer_code(self, typ='decreasing', side='right'):
                 a=self(i)
                 for j in range(i-self.k, i):
                     b=self(j)
-                    #A small rotation is necessary for the reduced word from
-                    #the lehmer code to match the element.
+                    # A small rotation is necessary for the reduced word from
+                    # the Lehmer code to match the element.
                     if a < b:
                         code[i-1]+=((b-a)//(self.k+1)+1)
         elif typ[0] == 'i' and side[0] == 'l':
@@ -2348,6 +2346,7 @@ def from_lehmer_code(self, C, typ='decreasing', side='right'):
 
     Element = AffinePermutationTypeA
 
+
 class AffinePermutationGroupTypeC(AffinePermutationGroupGeneric):
     #------------------------
     #Type-specific methods.
diff --git a/src/sage/combinat/colored_permutations.py b/src/sage/combinat/colored_permutations.py
index eb139497a52..4ce14eb3f66 100644
--- a/src/sage/combinat/colored_permutations.py
+++ b/src/sage/combinat/colored_permutations.py
@@ -96,7 +96,7 @@ def _mul_(self, other):
         p = self._perm._left_to_right_multiply_on_right(other._perm)
         return self.__class__(self.parent(), colors, p)
 
-    def inverse(self):
+    def __invert__(self):
         """
         Return the inverse of ``self``.
 
@@ -104,7 +104,7 @@ def inverse(self):
 
             sage: C = ColoredPermutations(4, 3)
             sage: s1,s2,t = C.gens()
-            sage: ~t
+            sage: ~t  # indirect doctest
             [[0, 0, 3], [1, 2, 3]]
             sage: all(x * ~x == C.one() for x in C.gens())
             True
@@ -114,8 +114,6 @@ def inverse(self):
                               tuple([-self._colors[i - 1] for i in ip]),  # -1 for indexing
                               ip)
 
-    __invert__ = inverse
-
     def __eq__(self, other):
         """
         Check equality.
@@ -981,7 +979,7 @@ def _mul_(self, other):
         p = self._perm._left_to_right_multiply_on_right(other._perm)
         return self.__class__(self.parent(), colors, p)
 
-    def inverse(self):
+    def __invert__(self):
         """
         Return the inverse of ``self``.
 
@@ -990,7 +988,7 @@ def inverse(self):
             sage: S = SignedPermutations(4)
             sage: s1,s2,s3,s4 = S.gens()
             sage: x = s4*s1*s2*s3*s4
-            sage: ~x
+            sage: ~x   # indirect doctest
             [2, 3, -4, -1]
             sage: x * ~x == S.one()
             True
@@ -1000,8 +998,6 @@ def inverse(self):
                               tuple([self._colors[i - 1] for i in ip]),  # -1 for indexing
                               ip)
 
-    __invert__ = inverse
-
     def __iter__(self):
         """
         Iterate over ``self``.
diff --git a/src/sage/combinat/root_system/fundamental_group.py b/src/sage/combinat/root_system/fundamental_group.py
index 7c097ad7fe3..53117f4213c 100644
--- a/src/sage/combinat/root_system/fundamental_group.py
+++ b/src/sage/combinat/root_system/fundamental_group.py
@@ -249,7 +249,7 @@ def _repr_(self):
         """
         return self.parent()._prefix + "[" + repr(self.value()) + "]"
 
-    def inverse(self):
+    def __invert__(self):
         r"""
         Return the inverse element of ``self``.
 
@@ -257,7 +257,7 @@ def inverse(self):
 
             sage: from sage.combinat.root_system.fundamental_group import FundamentalGroupOfExtendedAffineWeylGroup
             sage: F = FundamentalGroupOfExtendedAffineWeylGroup(['A',3,1])
-            sage: F(1).inverse()
+            sage: F(1).inverse()   # indirect doctest
             pi[3]
             sage: F = FundamentalGroupOfExtendedAffineWeylGroup(['E',6,1], prefix="f")
             sage: F(1).inverse()
@@ -266,8 +266,6 @@ def inverse(self):
         par = self.parent()
         return self.__class__(par, par.dual_node(self.value()))
 
-    __invert__ = inverse
-
     def _richcmp_(self, x, op):
         r"""
         Compare ``self`` with `x`.
diff --git a/src/sage/geometry/hyperbolic_space/hyperbolic_isometry.py b/src/sage/geometry/hyperbolic_space/hyperbolic_isometry.py
index 418e3eccbc5..bcdbde6063d 100644
--- a/src/sage/geometry/hyperbolic_space/hyperbolic_isometry.py
+++ b/src/sage/geometry/hyperbolic_space/hyperbolic_isometry.py
@@ -323,7 +323,7 @@ def matrix(self):
         """
         return self._matrix
 
-    def inverse(self):
+    def __invert__(self):
         r"""
         Return the inverse of the isometry ``self``.
 
@@ -331,13 +331,11 @@ def inverse(self):
 
             sage: UHP = HyperbolicPlane().UHP()
             sage: A = UHP.get_isometry(matrix(2,[4,1,3,2]))
-            sage: B = A.inverse()
+            sage: B = A.inverse()   # indirect doctest
             sage: A*B == UHP.get_isometry(identity_matrix(2))
             True
         """
-        return self.__class__(self.domain(), self.matrix().inverse())
-
-    __invert__ = inverse
+        return self.__class__(self.domain(), self.matrix().__invert__())
 
     def is_identity(self):
         """
diff --git a/src/sage/groups/abelian_gps/element_base.py b/src/sage/groups/abelian_gps/element_base.py
index d5b93a3f918..c1eec7ecb1f 100644
--- a/src/sage/groups/abelian_gps/element_base.py
+++ b/src/sage/groups/abelian_gps/element_base.py
@@ -15,7 +15,7 @@
 #  Copyright (C) 2012 Volker Braun  <vbraun.name@gmail.com>
 #
 #  Distributed under the terms of the GNU General Public License (GPL)
-#                  http://www.gnu.org/licenses/
+#                  https://www.gnu.org/licenses/
 ###########################################################################
 
 from sage.structure.element import MultiplicativeGroupElement
@@ -298,14 +298,14 @@ def __pow__(self, n):
                       for e,order in zip(self._exponents, G.gens_orders()) ]
         return G.element_class(G, exponents)
 
-    def inverse(self):
+    def __invert__(self):
         """
-        Returns the inverse element.
+        Return the inverse element.
 
         EXAMPLES::
 
             sage: G.<a,b> = AbelianGroup([0,5])
-            sage: a.inverse()
+            sage: a.inverse()  # indirect doctest
             a^-1
             sage: a.__invert__()
             a^-1
@@ -319,12 +319,10 @@ def inverse(self):
             (-1, 4)
         """
         G = self.parent()
-        exponents = [ (-e)%order if order!=0 else -e
-                      for e,order in zip(self._exponents, G.gens_orders()) ]
+        exponents = [(-e) % order if order != 0 else -e
+                     for e, order in zip(self._exponents, G.gens_orders())]
         return G.element_class(G, exponents)
 
-    __invert__ = inverse
-
     def is_trivial(self):
         """
         Test whether ``self`` is the trivial group element ``1``.
diff --git a/src/sage/groups/abelian_gps/values.py b/src/sage/groups/abelian_gps/values.py
index 288fb95b93c..e3d681af428 100644
--- a/src/sage/groups/abelian_gps/values.py
+++ b/src/sage/groups/abelian_gps/values.py
@@ -330,14 +330,14 @@ def __pow__(self, n):
         pow_self._value = pow(self.value(), m)
         return pow_self
 
-    def inverse(self):
+    def __invert__(self):
         """
         Return the inverse element.
 
         EXAMPLES::
 
             sage: G.<a,b> = AbelianGroupWithValues([2,-1], [0,4])
-            sage: a.inverse()
+            sage: a.inverse()   # indirect doctest
             a^-1
             sage: a.inverse().value()
             1/2
@@ -350,13 +350,10 @@ def inverse(self):
             sage: (a*b).inverse().value()
             -1/2
         """
-        m = AbelianGroupElement.inverse(self)
+        m = AbelianGroupElement.__invert__(self)
         m._value = ~self.value()
         return m
 
-    __invert__ = inverse
-
-
 
 class AbelianGroupWithValues_class(AbelianGroup_class):
     """
diff --git a/src/sage/groups/affine_gps/group_element.py b/src/sage/groups/affine_gps/group_element.py
index 72d2a4d77cf..8ff43ccc365 100644
--- a/src/sage/groups/affine_gps/group_element.py
+++ b/src/sage/groups/affine_gps/group_element.py
@@ -404,7 +404,7 @@ def _act_on_(self, x, self_on_left):
         if self_on_left:
             return self(x)
 
-    def inverse(self):
+    def __invert__(self):
         """
         Return the inverse group element.
 
@@ -422,19 +422,17 @@ def inverse(self):
             sage: ~g
                   [1 1]     [1]
             x |-> [0 1] x + [0]
-            sage: g * g.inverse()
+            sage: g * g.inverse()   # indirect doctest
                   [1 0]     [0]
             x |-> [0 1] x + [0]
             sage: g * g.inverse() == g.inverse() * g == G(1)
             True
         """
         parent = self.parent()
-        A = parent.matrix_space()(self._A.inverse())
-        b = -A*self.b()
+        A = parent.matrix_space()(~self._A)
+        b = -A * self.b()
         return parent.element_class(parent, A, b, check=False)
 
-    __invert__ = inverse
-
     def _richcmp_(self, other, op):
         """
         Compare ``self`` with ``other``.
diff --git a/src/sage/groups/group_exp.py b/src/sage/groups/group_exp.py
index bf0db4aa837..3ffa13a6ebf 100644
--- a/src/sage/groups/group_exp.py
+++ b/src/sage/groups/group_exp.py
@@ -211,20 +211,18 @@ def __init__(self, parent, x):
             raise ValueError("%s is not an element of %s" % (x, parent._G))
         ElementWrapper.__init__(self, parent, x)
 
-    def inverse(self):
+    def __invert__(self):
         r"""
         Invert the element ``self``.
 
         EXAMPLES::
 
             sage: EZ = GroupExp()(ZZ)
-            sage: EZ(-3).inverse()
+            sage: EZ(-3).inverse()  # indirect doctest
             3
         """
         return GroupExpElement(self.parent(), -self.value)
 
-    __invert__ = inverse
-
     def __mul__(self, x):
         r"""
         Multiply ``self`` by `x`.
diff --git a/src/sage/groups/group_semidirect_product.py b/src/sage/groups/group_semidirect_product.py
index e7e87530d1c..fad2978d443 100644
--- a/src/sage/groups/group_semidirect_product.py
+++ b/src/sage/groups/group_semidirect_product.py
@@ -58,9 +58,9 @@ def wrapper(prefix, s):
             return gstr
         return gstr + " * " + hstr
 
-    def inverse(self):
+    def __invert__(self):
         r"""
-        The inverse of ``self``.
+        Return the inverse of ``self``.
 
         EXAMPLES::
 
@@ -75,19 +75,16 @@ def inverse(self):
             s1*s2 * t[2*alpha[1] + 2*alpha[2]]
             sage: g.inverse()
             s2*s1 * t[2*alpha[1]]
-
         """
         par = self.parent()
         g = self.cartesian_projection(0)
         h = self.cartesian_projection(1)
 
         if par.act_to_right():
-            return self.__class__(par,(~g, par._twist(g,~h)))
+            return self.__class__(par, (~g, par._twist(g, ~h)))
         else:
             hi = ~h
-            return self.__class__(par,(par._twist(hi,~g),hi))
-
-    __invert__ = inverse
+            return self.__class__(par, (par._twist(hi, ~g), hi))
 
     def to_opposite(self):
         r"""
diff --git a/src/sage/modular/pollack_stevens/sigma0.py b/src/sage/modular/pollack_stevens/sigma0.py
index 6ff9b24b551..eed9e244cd2 100644
--- a/src/sage/modular/pollack_stevens/sigma0.py
+++ b/src/sage/modular/pollack_stevens/sigma0.py
@@ -295,15 +295,17 @@ def matrix(self):
         """
         return self._mat
 
-    def inverse(self):
+    def __invert__(self):
         r"""
-        Return the inverse of self. This will raise an error if the result is not in the monoid.
+        Return the inverse of ``self``.
+
+        This will raise an error if the result is not in the monoid.
 
         EXAMPLES::
 
             sage: from sage.modular.pollack_stevens.sigma0 import Sigma0
             sage: s = Sigma0(3)([1,4,3,13])
-            sage: s.inverse()
+            sage: s.inverse()    # indirect doctest
             [13 -4]
             [-3  1]
             sage: Sigma0(3)([1, 0, 0, 3]).inverse()
diff --git a/src/sage/monoids/free_monoid_element.py b/src/sage/monoids/free_monoid_element.py
index e9c04dca256..7345a251464 100644
--- a/src/sage/monoids/free_monoid_element.py
+++ b/src/sage/monoids/free_monoid_element.py
@@ -21,7 +21,7 @@
 #  See the GNU General Public License for more details; the full text
 #  is available at:
 #
-#                  http://www.gnu.org/licenses/
+#                  https://www.gnu.org/licenses/
 #*****************************************************************************
 
 from sage.rings.integer import Integer
@@ -99,7 +99,7 @@ def __hash__(self):
 
     def __iter__(self):
         """
-        Returns an iterator which yields tuples of variable and exponent.
+        Return an iterator which yields tuples of variable and exponent.
 
         EXAMPLES::
 
@@ -254,6 +254,9 @@ def _mul_(self, y):
                 z._element_list = x_elt[:k] + [ m ] + y_elt[1:]
         return z
 
+    def __invert__(self):
+        raise NotImplementedError
+
     def __len__(self):
         """
         Return the degree of the monoid element ``self``, where each
diff --git a/src/sage/rings/number_field/class_group.py b/src/sage/rings/number_field/class_group.py
index 46d0ca8c9d3..04e1b06983a 100644
--- a/src/sage/rings/number_field/class_group.py
+++ b/src/sage/rings/number_field/class_group.py
@@ -184,7 +184,7 @@ def inverse(self):
             sage: ~G(2, a)
             Fractional ideal class (2, a^2 + 2*a - 1)
         """
-        m = AbelianGroupElement.inverse(self)
+        m = AbelianGroupElement.__invert__(self)
         m._value = (~self.ideal()).reduce_equiv()
         return m
 
diff --git a/src/sage/rings/polynomial/polynomial_quotient_ring.py b/src/sage/rings/polynomial/polynomial_quotient_ring.py
index 66af8957b9d..f9529952d59 100644
--- a/src/sage/rings/polynomial/polynomial_quotient_ring.py
+++ b/src/sage/rings/polynomial/polynomial_quotient_ring.py
@@ -321,7 +321,7 @@ class of the category, and store the current class of the quotient
         sage: isinstance(Q.an_element(),Q.element_class)
         True
         sage: [s for s in dir(Q.category().element_class) if not s.startswith('_')]
-        ['cartesian_product', 'inverse_of_unit', 'is_idempotent', 'is_one', 'is_unit', 'lift', 'powers']
+        ['cartesian_product', 'inverse', 'inverse_of_unit', 'is_idempotent', 'is_one', 'is_unit', 'lift', 'powers']
         sage: first_class = Q.__class__
 
     We try to find out whether `Q` is a field. Indeed it is, and thus its category,
@@ -339,6 +339,7 @@ class of the category, and store the current class of the quotient
          'euclidean_degree',
          'factor',
          'gcd',
+         'inverse',
          'inverse_of_unit',
          'is_idempotent',
          'is_one',
@@ -1029,8 +1030,10 @@ def is_field(self, proof = True):
         try:
             ret = ret and self.modulus().is_irreducible()
         except NotImplementedError:
-            if proof: raise
-            else: ret = False
+            if proof:
+                raise
+            else:
+                ret = False
 
         if ret:
             from sage.categories.all import Fields
@@ -1202,7 +1205,8 @@ def _S_decomposition(self, S):
             j = 0
             for D_iso,_ in iso_classes:
                 if D_abs.is_isomorphic(D_iso):
-                    seen_before = True; break
+                    seen_before = True
+                    break
                 j += 1
             if not seen_before:
                 S_abs = []
diff --git a/src/sage/structure/element.pyx b/src/sage/structure/element.pyx
index f145e66c7a1..9ac162cbc54 100644
--- a/src/sage/structure/element.pyx
+++ b/src/sage/structure/element.pyx
@@ -2611,12 +2611,6 @@ cdef class MultiplicativeGroupElement(MonoidElement):
         """
         return self * ~right
 
-    def __invert__(self):
-        r"""
-        Return the inverse of ``self``.
-        """
-        return self._parent.one() / self
-
 
 def is_RingElement(x):
     """
@@ -2624,6 +2618,7 @@ def is_RingElement(x):
     """
     return isinstance(x, RingElement)
 
+
 cdef class RingElement(ModuleElement):
     cpdef _mul_(self, other):
         """