From ab8f9c64cc38def1b3c8338c1e38b6290894606d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Chapoton?= <chapoton@unistra.fr>
Date: Fri, 7 Nov 2025 18:01:15 +0100
Subject: [PATCH] some type annotations in algebras,coding,graphs

---
 src/sage/algebras/clifford_algebra.py         | 16 ++++++-------
 .../finite_dimensional_algebra_ideal.py       |  4 ++--
 .../letterplace/letterplace_ideal.pyx         |  4 ++--
 .../lie_algebras/affine_lie_algebra.py        | 10 ++++----
 .../algebras/lie_algebras/bgg_dual_module.py  |  8 +++----
 src/sage/algebras/lie_algebras/subalgebra.py  |  8 ++++---
 .../algebras/quatalg/quaternion_algebra.py    | 23 ++++++++++---------
 .../algebras/steenrod/steenrod_algebra.py     |  2 +-
 src/sage/coding/abstract_code.py              |  4 ++--
 src/sage/coding/cyclic_code.py                | 18 +++++++--------
 src/sage/coding/linear_code_no_metric.py      | 15 ++++++------
 src/sage/graphs/independent_sets.pyx          |  4 ++--
 src/sage/graphs/pq_trees.py                   |  6 ++---
 src/sage/graphs/views.pyx                     | 12 +++++-----
 14 files changed, 69 insertions(+), 65 deletions(-)

diff --git a/src/sage/algebras/clifford_algebra.py b/src/sage/algebras/clifford_algebra.py
index 945db75f991..cffa86d0c17 100644
--- a/src/sage/algebras/clifford_algebra.py
+++ b/src/sage/algebras/clifford_algebra.py
@@ -51,7 +51,7 @@ class CliffordAlgebraIndices(UniqueRepresentation, Parent):
     A facade parent for the indices of Clifford algebra.
     Users should not create instances of this class directly.
     """
-    def __init__(self, Qdim, degree=None):
+    def __init__(self, Qdim, degree=None) -> None:
         r"""
         Initialize ``self``.
 
@@ -271,7 +271,7 @@ def __iter__(self):
                 yield FrozenBitset(C)
             k += 1
 
-    def __contains__(self, elt):
+    def __contains__(self, elt) -> bool:
         r"""
         Check containment of ``elt`` in ``self``.
 
@@ -503,7 +503,7 @@ def __classcall_private__(cls, Q, names=None):
                 raise ValueError("the number of variables does not match the number of generators")
         return super().__classcall__(cls, Q, names)
 
-    def __init__(self, Q, names, category=None):
+    def __init__(self, Q, names, category=None) -> None:
         r"""
         Initialize ``self``.
 
@@ -1463,7 +1463,7 @@ def __classcall_private__(cls, R, names=None, n=None):
                 raise ValueError("the number of variables does not match the number of generators")
         return super().__classcall__(cls, R, names)
 
-    def __init__(self, R, names):
+    def __init__(self, R, names) -> None:
         """
         Initialize ``self``.
 
@@ -2124,7 +2124,7 @@ def __classcall__(cls, E, s_coeff):
         from sage.sets.family import Family
         return super().__classcall__(cls, E, Family(d))
 
-    def __init__(self, E, s_coeff):
+    def __init__(self, E, s_coeff) -> None:
         """
         Initialize ``self``.
 
@@ -2538,7 +2538,7 @@ class ExteriorAlgebraCoboundary(ExteriorAlgebraDifferential):
 
     - :wikipedia:`Exterior_algebra#Differential_geometry`
     """
-    def __init__(self, E, s_coeff):
+    def __init__(self, E, s_coeff) -> None:
         """
         Initialize ``self``.
 
@@ -2733,7 +2733,7 @@ class ExteriorAlgebraIdeal(Ideal_nc):
         sage: xbar * ybar
         0
     """
-    def __init__(self, ring, gens, coerce=True, side='twosided'):
+    def __init__(self, ring, gens, coerce=True, side='twosided') -> None:
         """
         Initialize ``self``.
 
@@ -2815,7 +2815,7 @@ def _contains_(self, f):
         """
         return not self.reduce(f)
 
-    def __richcmp__(self, other, op):
+    def __richcmp__(self, other, op) -> bool:
         """
         Compare ``self`` and ``other``.
 
diff --git a/src/sage/algebras/finite_dimensional_algebras/finite_dimensional_algebra_ideal.py b/src/sage/algebras/finite_dimensional_algebras/finite_dimensional_algebra_ideal.py
index a25b5bdb4f1..19b76c8a5e4 100644
--- a/src/sage/algebras/finite_dimensional_algebras/finite_dimensional_algebra_ideal.py
+++ b/src/sage/algebras/finite_dimensional_algebras/finite_dimensional_algebra_ideal.py
@@ -47,7 +47,7 @@ class FiniteDimensionalAlgebraIdeal(Ideal_generic):
         sage: A.ideal(A([0,1]))
         Ideal (e1) of Finite-dimensional algebra of degree 2 over Finite Field of size 3
     """
-    def __init__(self, A, gens=None, given_by_matrix=False):
+    def __init__(self, A, gens=None, given_by_matrix=False) -> bool:
         """
         EXAMPLES::
 
@@ -138,7 +138,7 @@ def _richcmp_(self, other, op):
         elif op == op_GE or op == op_GT:
             return other.vector_space().is_subspace(self.vector_space())
 
-    def __contains__(self, elt):
+    def __contains__(self, elt) -> bool:
         """
         EXAMPLES::
 
diff --git a/src/sage/algebras/letterplace/letterplace_ideal.pyx b/src/sage/algebras/letterplace/letterplace_ideal.pyx
index b504b237582..b80446cdbe4 100644
--- a/src/sage/algebras/letterplace/letterplace_ideal.pyx
+++ b/src/sage/algebras/letterplace/letterplace_ideal.pyx
@@ -155,7 +155,7 @@ class LetterplaceIdeal(Ideal_nc):
         sage: (z*I.0-x*y*z).normal_form(I)
         -y*x*z + z*z
     """
-    def __init__(self, ring, gens, coerce=True, side='twosided'):
+    def __init__(self, ring, gens, coerce=True, side='twosided') -> None:
         """
         INPUT:
 
@@ -334,7 +334,7 @@ class LetterplaceIdeal(Ideal_nc):
         self.__GB.__uptodeg = degbound
         return self.__GB
 
-    def __contains__(self, x):
+    def __contains__(self, x) -> bool:
         """
         The containment test is based on a normal form computation.
 
diff --git a/src/sage/algebras/lie_algebras/affine_lie_algebra.py b/src/sage/algebras/lie_algebras/affine_lie_algebra.py
index 02fefb8e623..43eea05c7bf 100644
--- a/src/sage/algebras/lie_algebras/affine_lie_algebra.py
+++ b/src/sage/algebras/lie_algebras/affine_lie_algebra.py
@@ -106,7 +106,7 @@ def __classcall_private__(cls, arg0, cartan_type=None, kac_moody=True):
             return UntwistedAffineLieAlgebra(g, kac_moody=kac_moody)
         return TwistedAffineLieAlgebra(arg0, cartan_type, kac_moody=kac_moody)
 
-    def __init__(self, g, cartan_type, names, kac_moody):
+    def __init__(self, g, cartan_type, names, kac_moody) -> None:
         """
         Initialize ``self``.
 
@@ -578,7 +578,7 @@ class UntwistedAffineLieAlgebra(AffineLieAlgebra):
         sage: D.d()
         0
     """
-    def __init__(self, g, kac_moody):
+    def __init__(self, g, kac_moody) -> None:
         """
         Initialize ``self``.
 
@@ -671,7 +671,7 @@ class TwistedAffineLieAlgebra(AffineLieAlgebra):
     weights in this representation with the roots of type `B_n` and
     the double all of its short roots.
     """
-    def __init__(self, R, cartan_type, kac_moody):
+    def __init__(self, R, cartan_type, kac_moody) -> None:
         """
         Initialize ``self``.
 
@@ -1107,7 +1107,7 @@ def __classcall_private__(cls, cartan_type):
             raise ValueError("the Cartan type must be a twisted affine type")
         return super().__classcall__(cls, cartan_type)
 
-    def __init__(self, cartan_type):
+    def __init__(self, cartan_type) -> None:
         """
         Initialize ``self``.
 
@@ -1141,7 +1141,7 @@ def __init__(self, cartan_type):
         from sage.categories.infinite_enumerated_sets import InfiniteEnumeratedSets
         super().__init__(facade=facade, category=InfiniteEnumeratedSets())
 
-    def __contains__(self, x):
+    def __contains__(self, x) -> bool:
         """
         Return if ``x`` is contained in ``self``.
 
diff --git a/src/sage/algebras/lie_algebras/bgg_dual_module.py b/src/sage/algebras/lie_algebras/bgg_dual_module.py
index eb6814a5d7a..a3c7e4a3ce9 100644
--- a/src/sage/algebras/lie_algebras/bgg_dual_module.py
+++ b/src/sage/algebras/lie_algebras/bgg_dual_module.py
@@ -100,7 +100,7 @@ class BGGDualModule(CombinatorialFreeModule):
 
     - [Humphreys08]_
     """
-    def __init__(self, module):
+    def __init__(self, module) -> None:
         r"""
         Initialize ``self``.
 
@@ -458,7 +458,7 @@ def __classcall__(cls, simple, prefix='f', **kwds):
         """
         return super(IndexedMonoid, cls).__classcall__(cls, simple, prefix=prefix, **kwds)
 
-    def __init__(self, simple, prefix, category=None, **kwds):
+    def __init__(self, simple, prefix, category=None, **kwds) -> None:
         r"""
         Initialize ``self``.
 
@@ -591,7 +591,7 @@ def weight_space_basis(self, mu):
             self._construct_next_level()
         return self._weight_space_bases.get(mu, [])
 
-    def __contains__(self, m):
+    def __contains__(self, m) -> bool:
         r"""
         Check if ``m`` is contained in ``self``.
 
@@ -815,7 +815,7 @@ def __classcall_private__(cls, g, weight, *args, **kwds):
             return FiniteDimensionalSimpleModule(g, weight, *args, **kwds)
         return super().__classcall__(cls, g, weight, *args, **kwds)
 
-    def __init__(self, g, weight, prefix='f', basis_key=None, **kwds):
+    def __init__(self, g, weight, prefix='f', basis_key=None, **kwds) -> None:
         r"""
         Initialize ``self``.
 
diff --git a/src/sage/algebras/lie_algebras/subalgebra.py b/src/sage/algebras/lie_algebras/subalgebra.py
index a4b535a3b32..cd1e42557ef 100644
--- a/src/sage/algebras/lie_algebras/subalgebra.py
+++ b/src/sage/algebras/lie_algebras/subalgebra.py
@@ -260,7 +260,8 @@ def __classcall_private__(cls, ambient, gens, ideal_of=None,
         return super().__classcall__(cls, ambient, gens, ideal_of,
                                      order, category)
 
-    def __init__(self, ambient, gens, ideal_of, order=None, category=None):
+    def __init__(self, ambient, gens, ideal_of,
+                 order=None, category=None) -> None:
         r"""
         Initialize ``self``.
 
@@ -302,7 +303,7 @@ def __init__(self, ambient, gens, ideal_of, order=None, category=None):
         f = SetMorphism(H, self.lift)
         ambient.register_coercion(f)
 
-    def __contains__(self, x):
+    def __contains__(self, x) -> bool:
         r"""
         Return ``True`` if ``x`` is an element of ``self``.
 
@@ -338,7 +339,8 @@ def __getitem__(self, x):
         If `x` is a pair `(a, b)`, return the Lie bracket `[a, b]`.
         Otherwise try to return the `x`-th element of ``self``.
 
-        This replicates the convenience syntax for Lie brackets of Lie algebras.
+        This replicates the convenience syntax for Lie brackets
+        of Lie algebras.
 
         EXAMPLES::
 
diff --git a/src/sage/algebras/quatalg/quaternion_algebra.py b/src/sage/algebras/quatalg/quaternion_algebra.py
index 8b75f3ed19f..7c0b0b287b7 100644
--- a/src/sage/algebras/quatalg/quaternion_algebra.py
+++ b/src/sage/algebras/quatalg/quaternion_algebra.py
@@ -823,7 +823,7 @@ class QuaternionAlgebra_ab(QuaternionAlgebra_abstract):
         sage: QuaternionAlgebra(QQ, -7, -21)  # indirect doctest
         Quaternion Algebra (-7, -21) with base ring Rational Field
     """
-    def __init__(self, base_ring, a, b, names='i,j,k'):
+    def __init__(self, base_ring, a, b, names='i,j,k') -> None:
         """
         Create the quaternion algebra with `i^2 = a`, `j^2 = b`, and
         `ij = -ji = k`.
@@ -1234,7 +1234,7 @@ def invariants(self):
         """
         return self._a, self._b
 
-    def __eq__(self, other):
+    def __eq__(self, other) -> bool:
         """
         Compare ``self`` and ``other``.
 
@@ -1250,7 +1250,7 @@ def __eq__(self, other):
         return (self.base_ring() == other.base_ring() and
                 (self._a, self._b) == (other._a, other._b))
 
-    def __ne__(self, other):
+    def __ne__(self, other) -> bool:
         """
         Compare ``self`` and ``other``.
 
@@ -1263,7 +1263,7 @@ def __ne__(self, other):
         """
         return not self.__eq__(other)
 
-    def __hash__(self):
+    def __hash__(self) -> int:
         """
         Compute the hash of ``self``.
 
@@ -1985,7 +1985,7 @@ class QuaternionOrder(Parent):
         sage: type(QuaternionAlgebra(-1,-7).maximal_order())
         <class 'sage.algebras.quatalg.quaternion_algebra.QuaternionOrder_with_category'>
     """
-    def __init__(self, A, basis, check=True):
+    def __init__(self, A, basis, check=True) -> None:
         """
         INPUT:
 
@@ -2186,7 +2186,7 @@ def gen(self, n):
         """
         return self.__basis[n]
 
-    def __richcmp__(self, other, op):
+    def __richcmp__(self, other, op) -> bool:
         """
         Compare this quaternion order to ``other``.
 
@@ -2239,7 +2239,7 @@ def __richcmp__(self, other, op):
             return op == op_NE
         return richcmp(self.unit_ideal(), other.unit_ideal(), op)
 
-    def __hash__(self):
+    def __hash__(self) -> int:
         """
         Compute the hash of ``self``.
 
@@ -3013,7 +3013,8 @@ class QuaternionFractionalIdeal_rational(QuaternionFractionalIdeal):
     - ``check`` -- boolean (default: ``True``); if ``False``, do no type
       checking.
     """
-    def __init__(self, Q, basis, left_order=None, right_order=None, check=True):
+    def __init__(self, Q, basis, left_order=None,
+                 right_order=None, check=True) -> None:
         """
         EXAMPLES::
 
@@ -3267,7 +3268,7 @@ def right_order(self):
             self.__right_order = self._compute_order(side='right')
         return self.__right_order
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         """
         Return string representation of this quaternion fractional ideal.
 
@@ -3361,7 +3362,7 @@ def _richcmp_(self, right, op):
         """
         return self.free_module().__richcmp__(right.free_module(), op)
 
-    def __hash__(self):
+    def __hash__(self) -> int:
         """
         Return the hash of ``self``.
 
@@ -4165,7 +4166,7 @@ def is_principal(self, certificate=False):
         # find an element of minimal norm in self; see [Piz1980]_, Corollary 1.20.
         return True, self.minimal_element()
 
-    def __contains__(self, x):
+    def __contains__(self, x) -> bool:
         """
         Return whether ``x`` is in ``self``.
 
diff --git a/src/sage/algebras/steenrod/steenrod_algebra.py b/src/sage/algebras/steenrod/steenrod_algebra.py
index 7aa7035034f..12752243744 100644
--- a/src/sage/algebras/steenrod/steenrod_algebra.py
+++ b/src/sage/algebras/steenrod/steenrod_algebra.py
@@ -2129,7 +2129,7 @@ def _element_constructor_(self, x):
                 return a.change_basis(self.basis_name())
         raise ValueError("element does not lie in this Steenrod algebra")
 
-    def __contains__(self, x):
+    def __contains__(self, x) -> bool:
         r"""
         Return ``True`` if ``self`` contains `x`.
 
diff --git a/src/sage/coding/abstract_code.py b/src/sage/coding/abstract_code.py
index 3d1fe305dbc..1ee2f922016 100644
--- a/src/sage/coding/abstract_code.py
+++ b/src/sage/coding/abstract_code.py
@@ -203,7 +203,7 @@ class AbstractCode(Parent):
     """
 
     def __init__(self, length, default_encoder_name=None,
-                 default_decoder_name=None, metric='Hamming'):
+                 default_decoder_name=None, metric='Hamming') -> None:
         r"""
         Initialize mandatory parameters that any code shares.
 
@@ -348,7 +348,7 @@ def __iter__(self):
         """
         raise RuntimeError("Please override __iter__ in the implementation of {}".format(self.parent()))
 
-    def __contains__(self, c):
+    def __contains__(self, c) -> bool:
         r"""
         Return an error message requiring to override ``__contains__`` in ``self``.
 
diff --git a/src/sage/coding/cyclic_code.py b/src/sage/coding/cyclic_code.py
index 80e8d68ef30..bd9017d346a 100644
--- a/src/sage/coding/cyclic_code.py
+++ b/src/sage/coding/cyclic_code.py
@@ -288,7 +288,7 @@ class CyclicCode(AbstractLinearCode):
     _registered_decoders = {}
 
     def __init__(self, generator_pol=None, length=None, code=None, check=True,
-                 D=None, field=None, primitive_root=None):
+                 D=None, field=None, primitive_root=None) -> None:
         r"""
         TESTS:
 
@@ -462,7 +462,7 @@ def __init__(self, generator_pol=None, length=None, code=None, check=True,
                                  "of powers and the length and the field, or "
                                  "a generator polynomial and the code length")
 
-    def __contains__(self, word):
+    def __contains__(self, word) -> bool:
         r"""
         Return ``True`` if ``word`` belongs to ``self``, ``False`` otherwise.
 
@@ -484,7 +484,7 @@ def __contains__(self, word):
         R = self._polynomial_ring
         return (g.divides(R(word.list())) and word in self.ambient_space())
 
-    def __eq__(self, other):
+    def __eq__(self, other) -> bool:
         r"""
         Test equality between CyclicCode objects.
 
@@ -836,7 +836,7 @@ class CyclicCodePolynomialEncoder(Encoder):
         Polynomial-style encoder for [7, 4] Cyclic Code over GF(2)
     """
 
-    def __init__(self, code):
+    def __init__(self, code) -> None:
         r"""
         EXAMPLES::
 
@@ -853,7 +853,7 @@ def __init__(self, code):
         self._polynomial_ring = code._polynomial_ring
         super().__init__(code)
 
-    def __eq__(self, other):
+    def __eq__(self, other) -> bool:
         r"""
         Test equality between CyclicCodePolynomialEncoder objects.
 
@@ -1005,7 +1005,7 @@ class CyclicCodeVectorEncoder(Encoder):
         Vector-style encoder for [7, 4] Cyclic Code over GF(2)
     """
 
-    def __init__(self, code):
+    def __init__(self, code) -> None:
         r"""
 
         EXAMPLES::
@@ -1023,7 +1023,7 @@ def __init__(self, code):
         self._polynomial_ring = code._polynomial_ring
         super().__init__(code)
 
-    def __eq__(self, other):
+    def __eq__(self, other) -> bool:
         r"""
         Test equality between CyclicCodeVectorEncoder objects.
 
@@ -1198,7 +1198,7 @@ class CyclicCodeSurroundingBCHDecoder(Decoder):
         sage: D
         Decoder through the surrounding BCH code of the [15, 10] Cyclic Code over GF(16)
     """
-    def __init__(self, code, **kwargs):
+    def __init__(self, code, **kwargs) -> None:
         r"""
 
         EXAMPLES::
@@ -1213,7 +1213,7 @@ def __init__(self, code, **kwargs):
         self._decoder_type = copy(self._bch_decoder.decoder_type())
         super().__init__(code, code.ambient_space(), "Vector")
 
-    def __eq__(self, other):
+    def __eq__(self, other) -> bool:
         r"""
         Test equality between CyclicCodeSurroundingBCHDecoder objects.
 
diff --git a/src/sage/coding/linear_code_no_metric.py b/src/sage/coding/linear_code_no_metric.py
index d357c6ac7e7..c5e1f372fac 100644
--- a/src/sage/coding/linear_code_no_metric.py
+++ b/src/sage/coding/linear_code_no_metric.py
@@ -138,7 +138,8 @@ class AbstractLinearCodeNoMetric(AbstractCode, Module):
     _registered_encoders = {}
     _registered_decoders = {}
 
-    def __init__(self, base_field, length, default_encoder_name, default_decoder_name, metric='Hamming'):
+    def __init__(self, base_field, length, default_encoder_name,
+                 default_decoder_name, metric='Hamming') -> None:
         """
         Initialize mandatory parameters that any linear code shares.
 
@@ -244,7 +245,7 @@ def generator_matrix(self, encoder_name=None, **kwargs):
         E = self.encoder(encoder_name, **kwargs)
         return E.generator_matrix()
 
-    def __eq__(self, other):
+    def __eq__(self, other) -> bool:
         r"""
         Test equality between two linear codes.
 
@@ -280,7 +281,7 @@ def __eq__(self, other):
         # the worst case does only one system solving.
         return all(c in self for c in other.gens())
 
-    def __ne__(self, other):
+    def __ne__(self, other) -> bool:
         r"""
         Test inequality of ``self`` and ``other``.
 
@@ -490,7 +491,7 @@ def syndrome(self, r):
         """
         return self.parity_check_matrix()*r
 
-    def __contains__(self, v):
+    def __contains__(self, v) -> bool:
         r"""
         Return ``True`` if `v` can be coerced into ``self``.
         Otherwise, return ``False``.
@@ -818,7 +819,7 @@ def __getitem__(self, i):
         codeword.set_immutable()
         return codeword
 
-    def __hash__(self):
+    def __hash__(self) -> int:
         r"""
         Return the hash value of ``self``.
 
@@ -1112,7 +1113,7 @@ class LinearCodeSystematicEncoder(Encoder):
         if LinearCodeSystematicEncoder is the default encoder
     """
 
-    def __init__(self, code, systematic_positions=None):
+    def __init__(self, code, systematic_positions=None) -> None:
         r"""
         EXAMPLES::
 
@@ -1134,7 +1135,7 @@ def __init__(self, code, systematic_positions=None):
             # Test that the systematic positions are an information set
             self.generator_matrix()
 
-    def __eq__(self, other):
+    def __eq__(self, other) -> bool:
         r"""
         Test equality between LinearCodeSystematicEncoder objects.
 
diff --git a/src/sage/graphs/independent_sets.pyx b/src/sage/graphs/independent_sets.pyx
index e46921b2c82..d416ec4ba9f 100644
--- a/src/sage/graphs/independent_sets.pyx
+++ b/src/sage/graphs/independent_sets.pyx
@@ -127,7 +127,7 @@ cdef class IndependentSets:
         ...
         ValueError: a is not a vertex of the graph
     """
-    def __init__(self, G, maximal=False, complement=False):
+    def __init__(self, G, maximal=False, complement=False) -> None:
         r"""
         Constructor for this class.
 
@@ -328,7 +328,7 @@ cdef class IndependentSets:
         from sage.rings.integer import Integer
         return Integer(i)
 
-    def __contains__(self, S):
+    def __contains__(self, S) -> bool:
         r"""
         Check whether the set is an independent set (possibly maximal).
 
diff --git a/src/sage/graphs/pq_trees.py b/src/sage/graphs/pq_trees.py
index 998e35fd845..869f9f909a4 100644
--- a/src/sage/graphs/pq_trees.py
+++ b/src/sage/graphs/pq_trees.py
@@ -285,7 +285,7 @@ class PQ:
     AUTHOR : Nathann Cohen
     """
 
-    def __init__(self, seq):
+    def __init__(self, seq) -> None:
         r"""
         Construction of a PQ-Tree.
 
@@ -329,7 +329,7 @@ def reverse(self):
 
         self._children.reverse()
 
-    def __contains__(self, v):
+    def __contains__(self, v) -> bool:
         r"""
         Test whether there exists an element of ``self`` containing
         an element ``v``.
@@ -378,7 +378,7 @@ def number_of_children(self):
         """
         return len(self._children)
 
-    def ordering(self):
+    def ordering(self) -> list:
         r"""
         Return the current ordering given by listing the leaves from
         left to right.
diff --git a/src/sage/graphs/views.pyx b/src/sage/graphs/views.pyx
index 8dd73c928d4..d1ee421ac3c 100644
--- a/src/sage/graphs/views.pyx
+++ b/src/sage/graphs/views.pyx
@@ -342,7 +342,7 @@ cdef class EdgesView:
 
     def __init__(self, G, vertices=None, vertices2=None, labels=True,
                  ignore_direction=False,
-                 sort=False, key=None, sort_vertices=True):
+                 sort=False, key=None, sort_vertices=True) -> None:
         """
         Construction of this :class:`EdgesView`.
 
@@ -385,7 +385,7 @@ cdef class EdgesView:
         self._sort_edges_key = key
         self._sort_vertices = sort_vertices
 
-    def __len__(self):
+    def __len__(self) -> int:
         """
         Return the number of edges in ``self``.
 
@@ -414,7 +414,7 @@ cdef class EdgesView:
             return self._graph.size()
         return sum(1 for _ in self)
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         """
         Return a string representation of ``self``.
 
@@ -499,7 +499,7 @@ cdef class EdgesView:
         else:
             yield from self._iter_unsorted()
 
-    def __bool__(self):
+    def __bool__(self) -> bool:
         """
         Check whether ``self`` is not empty.
 
@@ -517,7 +517,7 @@ cdef class EdgesView:
             return True
         return False
 
-    def __eq__(self, right):
+    def __eq__(self, right) -> bool:
         """
         Check whether ``self`` and ``right`` are equal.
 
@@ -587,7 +587,7 @@ cdef class EdgesView:
         # Check that the same edges are reported in the same order
         return all(es == eo for es, eo in zip(self, other))
 
-    def __contains__(self, e):
+    def __contains__(self, e) -> bool:
         """
         Check whether edge ``e`` is part of ``self``.