gh-38184: Deprecate is_FreeAlgebraQuotientElement, ...

    
<!-- ^ Please provide a concise and informative title. -->
<!-- ^ Don't put issue numbers in the title, do this in the PR
description below. -->
<!-- ^ For example, instead of "Fixes #12345" use "Introduce new method
to calculate 1 + 2". -->
<!-- v Describe your changes below in detail. -->
<!-- v Why is this change required? What problem does it solve? -->
<!-- v If this PR resolves an open issue, please link to it here. For
example, "Fixes #12345". -->



### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->

- [x] The title is concise and informative.
- [ ] The description explains in detail what this PR is about.
- [ ] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.

### ⌛ Dependencies

<!-- List all open PRs that this PR logically depends on. For example,
-->
<!-- - #12345: short description why this is a dependency -->
<!-- - #34567: ... -->
    
URL: #38184
Reported by: Matthias Köppe
Reviewer(s): Kwankyu Lee

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superseded import deprecation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)

src/sage/modular/modform/ambient_eps.py

@@ -124,7 +124,7 @@ def __init__(self, character, weight=2, base_ring=None, eis_only=False):
             sage: type(m)
             <class 'sage.modular.modform.ambient_eps.ModularFormsAmbient_eps_with_category'>
         """
-        if not dirichlet.is_DirichletCharacter(character):
+        if not isinstance(character, dirichlet.DirichletCharacter):
             raise TypeError("character (=%s) must be a Dirichlet character" % character)
         if base_ring is None:
             base_ring = character.base_ring()

src/sage/modular/modform/element.py

@@ -72,10 +72,18 @@ def is_ModularFormElement(x):
 
         sage: from sage.modular.modform.element import is_ModularFormElement
         sage: is_ModularFormElement(5)
+        doctest:warning...
+        DeprecationWarning: The function is_ModularFormElement is deprecated;
+        use 'isinstance(..., ModularFormElement)' instead.
+        See https://github.com/sagemath/sage/issues/38184 for details.
         False
         sage: is_ModularFormElement(ModularForms(11).0)
         True
     """
+    from sage.misc.superseded import deprecation
+    deprecation(38184,
+                "The function is_ModularFormElement is deprecated; "
+                "use 'isinstance(..., ModularFormElement)' instead.")
     return isinstance(x, ModularFormElement)
 
 
@@ -3265,7 +3273,7 @@ def __init__(self, parent, forms_datum):
                     k = ZZ(k)
                     if k == 0:
                         forms_dictionary[k] = parent.base_ring().coerce(f)
-                    elif is_ModularFormElement(f):
+                    elif isinstance(f, ModularFormElement):
                         if f.weight() == k:
                             if parent.group().is_subgroup(f.group()) and parent.base_ring().has_coerce_map_from(f.base_ring()):
                                 M = parent.modular_forms_of_weight(f.weight()).change_ring(parent.base_ring())
@@ -3280,7 +3288,7 @@ def __init__(self, parent, forms_datum):
                     raise ValueError('at least one key (%s) of the defining dictionary is not an integer' % (k))
         elif isinstance(forms_datum, list):
             for f in forms_datum:
-                if is_ModularFormElement(f):
+                if isinstance(f, ModularFormElement):
                     chi = f.character(compute=False)
                     if (chi is not None) and (not chi.is_trivial()):
                         raise NotImplementedError("graded modular forms for non-trivial characters is not yet implemented")

src/sage/modular/modform/hecke_operator_on_qexp.py

@@ -23,8 +23,8 @@
 
 lazy_import('sage.rings.number_field.number_field', 'CyclotomicField')
 
-from sage.modular.dirichlet import DirichletGroup, is_DirichletCharacter
-from .element import is_ModularFormElement
+from sage.modular.dirichlet import DirichletGroup, DirichletCharacter
+from .element import ModularFormElement
 
 def hecke_operator_on_qexp(f, n, k, eps=None,
                            prec=None, check=True, _return_list=False):
@@ -87,16 +87,16 @@ def hecke_operator_on_qexp(f, n, k, eps=None,
         # ZZ can coerce to GF(p), but QQ can't.
         eps = DirichletGroup(1, base_ring=ZZ)[0]
     if check:
-        if not (is_PowerSeries(f) or is_ModularFormElement(f)):
+        if not (is_PowerSeries(f) or isinstance(f, ModularFormElement)):
             raise TypeError("f (=%s) must be a power series or modular form" % f)
-        if not is_DirichletCharacter(eps):
+        if not isinstance(eps, DirichletCharacter):
             raise TypeError("eps (=%s) must be a Dirichlet character" % eps)
         k = Integer(k)
         n = Integer(n)
     v = []
 
     if prec is None:
-        if is_ModularFormElement(f):
+        if isinstance(f, ModularFormElement):
             # always want at least three coefficients, but not too many, unless
             # requested
             pr = max(f.prec(), f.parent().prec(), (n+1)*3)
@@ -123,7 +123,7 @@ def hecke_operator_on_qexp(f, n, k, eps=None,
             v.append(am)
     if _return_list:
         return v
-    if is_ModularFormElement(f):
+    if isinstance(f, ModularFormElement):
         R = f.parent()._q_expansion_ring()
     else:
         R = f.parent()

src/sage/modular/modform/ring.py

@@ -40,7 +40,7 @@
 from sage.structure.richcmp import richcmp_method, richcmp
 
 from .constructor import ModularForms
-from .element import is_ModularFormElement, GradedModularFormElement
+from .element import ModularFormElement, GradedModularFormElement
 from .space import ModularFormsSpace
 
 
@@ -517,7 +517,7 @@ def _element_constructor_(self, forms_datum):
             forms_dictionary = forms_datum
         elif isinstance(forms_datum, self.element_class):
             forms_dictionary = forms_datum._forms_dictionary
-        elif is_ModularFormElement(forms_datum):
+        elif isinstance(forms_datum, ModularFormElement):
             if self.group().is_subgroup(forms_datum.group()) and self.base_ring().has_coerce_map_from(forms_datum.base_ring()):
                 forms_dictionary = {forms_datum.weight(): forms_datum}
             else:

src/sage/modular/modform_hecketriangle/abstract_space.py

@@ -17,7 +17,7 @@
 from sage.matrix.constructor import matrix
 from sage.misc.cachefunc import cached_method
 from sage.misc.lazy_import import lazy_import
-from sage.modules.free_module_element import is_FreeModuleElement
+from sage.modules.free_module_element import FreeModuleElement
 from sage.modules.free_module_element import vector
 from sage.rings.infinity import infinity
 from sage.rings.integer import Integer
@@ -262,9 +262,9 @@ def _element_constructor_(self, el):
                 return self.construct_form(el)
             else:
                 return self.construct_quasi_form(el)
-        if is_FreeModuleElement(el) and (self.module() is P or self.ambient_module() is P):
+        if isinstance(el, FreeModuleElement) and (self.module() is P or self.ambient_module() is P):
             return self.element_from_ambient_coordinates(el)
-        if (not self.is_ambient()) and (isinstance(el, list) or isinstance(el, tuple) or is_FreeModuleElement(el)) and len(el) == self.rank():
+        if (not self.is_ambient()) and (isinstance(el, list) or isinstance(el, tuple) or isinstance(el, FreeModuleElement)) and len(el) == self.rank():
             try:
                 return self.element_from_coordinates(el)
             except (ArithmeticError, TypeError):

src/sage/modular/modsym/ambient.py

@@ -79,7 +79,7 @@ class ``ModularSymbolsAmbient``, derived from
 from sage.misc.latex import latex
 from sage.misc.verbose import verbose
 from sage.modular.arithgroup.arithgroup_element import M2Z
-from sage.modular.dirichlet import TrivialCharacter, is_DirichletCharacter
+from sage.modular.dirichlet import DirichletCharacter, TrivialCharacter
 from sage.modular.hecke.ambient_module import AmbientHeckeModule
 from sage.modular.cusps import Cusp
 from sage.modular.modsym.apply import apply_to_monomial
@@ -2171,7 +2171,7 @@ def twisted_winding_element(self, i, eps):
             sage: M.twisted_winding_element(0,eps)
             2*(1,23) - 2*(1,32) + 2*(1,34)
         """
-        if not is_DirichletCharacter(eps):
+        if not isinstance(eps, DirichletCharacter):
             raise TypeError("eps must be a Dirichlet character.")
         if (i < 0) or (i > self.weight() - 2):
             raise ValueError("i must be between 0 and k-2.")

src/sage/modular/modsym/boundary.py

@@ -93,7 +93,7 @@
 from sage.structure.richcmp import richcmp_method, richcmp
 
 import sage.modules.free_module as free_module
-from sage.modules.free_module_element import is_FreeModuleElement
+from sage.modules.free_module_element import FreeModuleElement
 
 import sage.modular.arithgroup.all as arithgroup
 import sage.modular.cusps as cusps
@@ -554,7 +554,7 @@ def __call__(self, x):
         elif isinstance(x, ManinSymbol):
             return self._coerce_in_manin_symbol(x)
 
-        elif element.is_ModularSymbolsElement(x):
+        elif isinstance(x, element.ModularSymbolsElement):
             M = x.parent()
             if not isinstance(M, ModularSymbolsAmbient):
                 raise TypeError("x (=%s) must be an element of a space of modular symbols of type ModularSymbolsAmbient" % x)
@@ -566,7 +566,7 @@ def __call__(self, x):
                 return self(0)
             return sum([c * self._coerce_in_manin_symbol(v) for c, v in S])
 
-        elif is_FreeModuleElement(x):
+        elif isinstance(x, FreeModuleElement):
             y = dict(enumerate(x))
             return BoundarySpaceElement(self, y)