gh-40262: Minor modernization by removing outdated workarounds
    
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Removing some old code that is only required for Python <= 3.10.

Minor stylistic cleanup of the touched files (mostly reordering of the
imports).

### 📝 Checklist

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- [ ] 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

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URL: #40262
Reported by: Tobias Diez
Reviewer(s): Frédéric Chapoton, Tobias Diez, user202729

Author: Release Manager

src/sage/misc/cython.py

@@ -22,15 +22,14 @@
 import builtins
 import os
 import re
-import sys
 import shutil
+import sys
 import webbrowser
 from pathlib import Path
 
-from sage.env import (SAGE_LOCAL, cython_aliases,
-                      sage_include_directories)
+from sage.env import SAGE_LOCAL, cython_aliases, sage_include_directories
 from sage.misc.cachefunc import cached_function
-from sage.misc.sage_ostools import restore_cwd, redirection
+from sage.misc.sage_ostools import redirection, restore_cwd
 from sage.misc.temporary_file import spyx_tmp, tmp_filename
 from sage.repl.user_globals import get_globals
 
@@ -355,20 +354,13 @@ def cython(filename, verbose=0, compile_message=False,
     includes = [os.getcwd()] + standard_includes
 
     # Now do the actual build, directly calling Cython and distutils
+    from distutils.log import set_verbosity
+
+    import Cython.Compiler.Options
     from Cython.Build import cythonize
     from Cython.Compiler.Errors import CompileError
-    import Cython.Compiler.Options
-
-    try:
-        from setuptools.dist import Distribution
-        from setuptools.extension import Extension
-    except ImportError:
-        # Fall back to distutils (stdlib); note that it is deprecated
-        # in Python 3.10, 3.11; https://www.python.org/dev/peps/pep-0632/
-        from distutils.dist import Distribution
-        from distutils.core import Extension
-
-    from distutils.log import set_verbosity
+    from setuptools.dist import Distribution
+    from setuptools.extension import Extension
     set_verbosity(verbose)
 
     Cython.Compiler.Options.annotate = annotate

src/sage/quadratic_forms/genera/genus.py

@@ -18,21 +18,22 @@
 #
 #                  https://www.gnu.org/licenses/
 # ****************************************************************************
-from pathlib import Path
 from copy import copy, deepcopy
+from pathlib import Path
 
-from sage.misc.lazy_import import lazy_import
-from sage.misc.misc_c import prod
-from sage.misc.cachefunc import cached_method
 from sage.arith.functions import lcm as LCM
 from sage.arith.misc import fundamental_discriminant
-from sage.matrix.matrix_space import MatrixSpace
 from sage.matrix.constructor import matrix
-from sage.rings.integer_ring import ZZ
-from sage.rings.rational_field import QQ
-from sage.rings.integer import Integer
+from sage.matrix.matrix_space import MatrixSpace
+from sage.misc.cachefunc import cached_method
+from sage.misc.lazy_import import lazy_import
+from sage.misc.misc_c import prod
 from sage.misc.verbose import verbose
 from sage.quadratic_forms.special_values import quadratic_L_function__exact
+from sage.rings.integer import Integer
+from sage.rings.integer_ring import ZZ
+from sage.rings.rational_field import QQ
+
 lazy_import('sage.quadratic_forms.genera.normal_form', '_min_nonsquare')
 lazy_import('sage.interfaces.magma', 'magma')
 
@@ -120,8 +121,7 @@ def genera(sig_pair, determinant, max_scale=None, even=False):
     return genera
 
 
-# #35557: In Python < 3.10, a staticmethod cannot be called directly
-_genera_staticmethod = staticmethod(genera)
+genera = staticmethod(genera)
 
 
 def _local_genera(p, rank, det_val, max_scale, even):
@@ -172,8 +172,8 @@ def _local_genera(p, rank, det_val, max_scale, even):
          Genus symbol at 5:     5^-2,
          Genus symbol at 5:     5^2]
     """
-    from sage.misc.mrange import cantor_product
     from sage.combinat.integer_lists.invlex import IntegerListsLex
+    from sage.misc.mrange import cantor_product
     scales_rks = []  # contains possibilities for scales and ranks
     for rkseq in IntegerListsLex(rank, length=max_scale + 1):  # rank sequences
         # sum(rkseq) = rank
@@ -2871,8 +2871,10 @@ def rational_representative(self):
             [0 0 0 0 0 0 1 0]
             [0 0 0 0 0 0 0 2]
         """
-        from sage.quadratic_forms.quadratic_form import QuadraticForm
-        from sage.quadratic_forms.quadratic_form import quadratic_form_from_invariants
+        from sage.quadratic_forms.quadratic_form import (
+            QuadraticForm,
+            quadratic_form_from_invariants,
+        )
         sminus = self.signature_pair_of_matrix()[1]
         det = self.determinant()
         m = self.rank()
@@ -2907,7 +2909,10 @@ def _compute_representative(self, LLL=True):
             ....:     G = genera((2,2), det, even=False)
             ....:     assert all(g==Genus(g.representative()) for g in G)
         """
-        from sage.modules.free_quadratic_module_integer_symmetric import IntegralLattice, local_modification
+        from sage.modules.free_quadratic_module_integer_symmetric import (
+            IntegralLattice,
+            local_modification,
+        )
         q = self.rational_representative()
         # the associated quadratic form xGx.T/2 should be integral
         L = IntegralLattice(4 * q).maximal_overlattice()
@@ -3059,15 +3064,19 @@ def representatives(self, backend=None, algorithm=None):
                 if self.signature_pair()[0] == 0:
                     e = ZZ(-1)
                 d = - 4 * self.determinant()
-                from sage.quadratic_forms.binary_qf import BinaryQF_reduced_representatives
+                from sage.quadratic_forms.binary_qf import (
+                    BinaryQF_reduced_representatives,
+                )
                 for q in BinaryQF_reduced_representatives(d, proper=False):
                     if q[1] % 2 == 0:  # we want integrality of the gram matrix
                         m = e*matrix(ZZ, 2, [q[0], q[1] // 2, q[1] // 2, q[2]])
                         if Genus(m) == self:
                             representatives.append(m)
             if n > 2:
                 from sage.quadratic_forms.quadratic_form import QuadraticForm
-                from sage.quadratic_forms.quadratic_form__neighbors import neighbor_iteration
+                from sage.quadratic_forms.quadratic_form__neighbors import (
+                    neighbor_iteration,
+                )
                 e = ZZ.one()
                 if not self.is_even():
                     e = ZZ(2)
@@ -3152,10 +3161,10 @@ def _standard_mass(self):
             sage: GS._standard_mass()                                                   # needs sage.symbolic
             1/48
         """
+        from sage.functions.gamma import gamma
+        from sage.functions.transcendental import zeta
         from sage.symbolic.constants import pi
         from sage.symbolic.ring import SR
-        from sage.functions.transcendental import zeta
-        from sage.functions.gamma import gamma
         n = self.dimension()
         if n % 2 == 0:
             s = n // 2