gh-38184: Deprecate `is_FreeAlgebraQuotientElement`, ...
    
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### ⌛ Dependencies

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URL: #38184
Reported by: Matthias Köppe
Reviewer(s): Kwankyu Lee

Author: Release Manager

src/sage/algebras/free_algebra_quotient_element.py

@@ -38,6 +38,10 @@ def is_FreeAlgebraQuotientElement(x):
 
         sage: H, (i,j,k) = sage.algebras.free_algebra_quotient.hamilton_quatalg(QQ)
         sage: sage.algebras.free_algebra_quotient_element.is_FreeAlgebraQuotientElement(i)
+        doctest:warning...
+        DeprecationWarning: The function is_FreeAlgebraQuotientElement is deprecated;
+        use 'isinstance(..., FreeAlgebraQuotientElement)' instead.
+        See https://github.com/sagemath/sage/issues/38184 for details.
         True
 
     Of course this is testing the data type::
@@ -47,6 +51,10 @@ def is_FreeAlgebraQuotientElement(x):
         sage: sage.algebras.free_algebra_quotient_element.is_FreeAlgebraQuotientElement(H(1))
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38184,
+                "The function is_FreeAlgebraQuotientElement is deprecated; "
+                "use 'isinstance(..., FreeAlgebraQuotientElement)' instead.")
     return isinstance(x, FreeAlgebraQuotientElement)
 
 

src/sage/categories/functor.pyx

@@ -96,15 +96,15 @@ cdef class Functor(SageObject):
         Category of rings
         sage: F.codomain()
         Category of commutative additive groups
-        sage: from sage.categories.functor import is_Functor
-        sage: is_Functor(F)
+        sage: from sage.categories.functor import Functor
+        sage: isinstance(F, Functor)
         True
         sage: I = IdentityFunctor(abgrps)
         sage: I
         The identity functor on Category of commutative additive groups
         sage: I.domain()
         Category of commutative additive groups
-        sage: is_Functor(I)
+        sage: isinstance(I, Functor)
         True
 
     Note that by default, an instance of the class Functor is coercion
@@ -422,12 +422,9 @@ cdef class Functor(SageObject):
 
 def is_Functor(x):
     """
-    Test whether the argument is a functor
-
-    NOTE:
+    Test whether the argument is a functor.
 
-    There is a deprecation warning when using it from top level.
-    Therefore we import it in our doc test.
+    This function is deprecated.
 
     EXAMPLES::
 
@@ -436,6 +433,10 @@ def is_Functor(x):
         sage: F1
         FractionField
         sage: is_Functor(F1)
+        doctest:warning...
+        DeprecationWarning: The function is_Functor is deprecated;
+        use 'isinstance(..., Functor)' instead.
+        See https://github.com/sagemath/sage/issues/38184 for details.
         True
         sage: is_Functor(FractionField)
         False
@@ -446,6 +447,10 @@ def is_Functor(x):
         True
 
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38184,
+                "The function is_Functor is deprecated; "
+                "use 'isinstance(..., Functor)' instead.")
     return isinstance(x, Functor)
 
 

src/sage/groups/abelian_gps/abelian_group_element.py

@@ -57,11 +57,19 @@ def is_AbelianGroupElement(x):
 
         sage: from sage.groups.abelian_gps.abelian_group_element import is_AbelianGroupElement
         sage: is_AbelianGroupElement(3)
+        doctest:warning...
+        DeprecationWarning: The function is_AbelianGroupElement is deprecated;
+        use 'isinstance(..., AbelianGroupElement)' instead.
+        See https://github.com/sagemath/sage/issues/38184 for details.
         False
         sage: F = AbelianGroup(5, [3,4,5,8,7], 'abcde')
         sage: is_AbelianGroupElement(F.0)
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38184,
+                "The function is_AbelianGroupElement is deprecated; "
+                "use 'isinstance(..., AbelianGroupElement)' instead.")
     return isinstance(x, AbelianGroupElement)
 
 

src/sage/groups/abelian_gps/dual_abelian_group.py

@@ -345,7 +345,7 @@ def __contains__(self, X):
             sage: A*B^2*D^7 in Fd
             True
         """
-        return X.parent() == self and is_DualAbelianGroupElement(X)
+        return X.parent() == self and isinstance(X, DualAbelianGroupElement)
 
     def order(self):
         """

src/sage/groups/abelian_gps/dual_abelian_group_element.py

@@ -71,10 +71,18 @@ def is_DualAbelianGroupElement(x) -> bool:
         sage: from sage.groups.abelian_gps.dual_abelian_group import is_DualAbelianGroupElement
         sage: F = AbelianGroup(5, [5,5,7,8,9], names=list("abcde")).dual_group()
         sage: is_DualAbelianGroupElement(F)
+        doctest:warning...
+        DeprecationWarning: The function is_DualAbelianGroupElement is deprecated;
+        use 'isinstance(..., DualAbelianGroupElement)' instead.
+        See https://github.com/sagemath/sage/issues/38184 for details.
         False
         sage: is_DualAbelianGroupElement(F.an_element())
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38184,
+                "The function is_DualAbelianGroupElement is deprecated; "
+                "use 'isinstance(..., DualAbelianGroupElement)' instead.")
     return isinstance(x, DualAbelianGroupElement)
 
 

src/sage/groups/perm_gps/permgroup_element.pyx

@@ -211,8 +211,16 @@ def is_PermutationGroupElement(x):
         sage: p = PermutationGroupElement([(1,2),(3,4,5)])
         sage: from sage.groups.perm_gps.permgroup_element import is_PermutationGroupElement
         sage: is_PermutationGroupElement(p)
+        doctest:warning...
+        DeprecationWarning: The function is_PermutationGroupElement is deprecated;
+        use 'isinstance(..., PermutationGroupElement)' instead.
+        See https://github.com/sagemath/sage/issues/38184 for details.
         True
     """
+    from sage.misc.superseded import deprecation_cython
+    deprecation_cython(38184,
+                       "The function is_PermutationGroupElement is deprecated; "
+                       "use 'isinstance(..., PermutationGroupElement)' instead.")
     return isinstance(x, PermutationGroupElement)
 
 

src/sage/homology/chain_complex_homspace.py

@@ -116,9 +116,17 @@ def is_ChainComplexHomspace(x):
         sage: C = T.chain_complex(augmented=True, cochain=True)
         sage: G = Hom(C, C)
         sage: is_ChainComplexHomspace(G)
+        doctest:warning...
+        DeprecationWarning: The function is_ChainComplexHomspace is deprecated;
+        use 'isinstance(..., ChainComplexHomspace)' instead.
+        See https://github.com/sagemath/sage/issues/38184 for details.
         True
 
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38184,
+                "The function is_ChainComplexHomspace is deprecated; "
+                "use 'isinstance(..., ChainComplexHomspace)' instead.")
     return isinstance(x, ChainComplexHomspace)
 
 

src/sage/matrix/matrix2.pyx

@@ -99,7 +99,7 @@ from sage.arith.numerical_approx cimport digits_to_bits
 
 import sage.modules.free_module
 from sage.matrix import berlekamp_massey
-from sage.modules.free_module_element import is_FreeModuleElement
+from sage.modules.free_module_element import FreeModuleElement
 from sage.matrix.matrix_misc import permanental_minor_polynomial
 
 from sage.misc.misc_c import prod
@@ -6153,7 +6153,7 @@ cdef class Matrix(Matrix1):
         """
         if v == 0:
             return []
-        if not is_FreeModuleElement(v):
+        if not isinstance(v, FreeModuleElement):
             raise TypeError("v must be a FreeModuleElement")
         VS = v.parent()
         V = VS.span([v])

src/sage/misc/latex.py

@@ -1934,7 +1934,7 @@ def png(x, filename, density=150, debug=False,
         ....:     png(ZZ[x], f.name)
     """
     import sage.plot.all
-    if sage.plot.graphics.is_Graphics(x):
+    if isinstance(x, sage.plot.graphics.Graphics):
         x.save(filename)
         return
     # if not graphics: create a string of latex code to write in a file

src/sage/modular/dirichlet.py

@@ -172,10 +172,18 @@ def is_DirichletCharacter(x) -> bool:
 
         sage: from sage.modular.dirichlet import is_DirichletCharacter
         sage: is_DirichletCharacter(trivial_character(3))
+        doctest:warning...
+        DeprecationWarning: The function is_DirichletCharacter is deprecated;
+        use 'isinstance(..., DirichletCharacter)' instead.
+        See https://github.com/sagemath/sage/issues/38184 for details.
         True
         sage: is_DirichletCharacter([1])
         False
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38184,
+                "The function is_DirichletCharacter is deprecated; "
+                "use 'isinstance(..., DirichletCharacter)' instead.")
     return isinstance(x, DirichletCharacter)
 
 
@@ -262,7 +270,7 @@ def __init__(self, parent, x, check=True):
             orders = parent.integers_mod().unit_group().gens_orders()
             if len(x) != len(orders):
                 raise ValueError("wrong number of values (= {}) on generators (want {})".format(x, len(orders)))
-            if free_module_element.is_FreeModuleElement(x):
+            if isinstance(x, free_module_element.FreeModuleElement):
                 x = parent._module(x)
                 if any(u * v for u, v in zip(x, orders)):
                     raise ValueError("values (= {} modulo {}) must have additive orders dividing {}, respectively"
@@ -276,7 +284,7 @@ def __init__(self, parent, x, check=True):
                                      .format(x, orders))
                 self.values_on_gens.set_cache(x)
         else:
-            if free_module_element.is_FreeModuleElement(x):
+            if isinstance(x, free_module_element.FreeModuleElement):
                 self.element.set_cache(x)
             else:
                 self.values_on_gens.set_cache(x)