gh-36177: fix and activate pycodestyle E305 in py files

    
fix and activate

-  pycodestyle E305 in py files
- pycodestyle E502 in pyx file (one fix only)

### 📝 Checklist

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
    
URL: #36177
Reported by: Frédéric Chapoton
Reviewer(s): David Coudert, Tobias Diez

.vscode/settings.json

@@ -27,7 +27,7 @@
     "python.linting.enabled": true,
     // The following pycodestyle arguments are the same as the pycodestyle-minimal
     // tox environnment, see the file SAGE_ROOT/src/tox.ini
-    "python.linting.pycodestyleArgs": ["--select= E111,E21,E222,E227,E25,E271,E303,E306,E401,E502,E701,E702,E703,E71,E72,W291,W293,W391,W605"],
+    "python.linting.pycodestyleArgs": ["--select= E111,E21,E222,E227,E25,E271,E303,E305,E306,E401,E502,E701,E702,E703,E71,E72,W291,W293,W391,W605"],
     "cSpell.words": [
         "furo",
         "Conda",

src/sage/algebras/lie_algebras/examples.py

@@ -309,6 +309,7 @@ def regular_vector_fields(R):
     from sage.algebras.lie_algebras.virasoro import LieAlgebraRegularVectorFields
     return LieAlgebraRegularVectorFields(R)
 
+
 witt = regular_vector_fields
 
 def pwitt(R, p):

src/sage/combinat/designs/bibd.py

@@ -1048,6 +1048,7 @@ def _PBD_4_5_8_9_12_closure(B):
             BB.append(X)
     return BB
 
+
 table_7_1 = {
     0:{'t':-4,'u':16,'s':2},
     1:{'t':-4,'u':17,'s':2},
@@ -1652,4 +1653,5 @@ def arc(self, s=2, solver=None, verbose=0, *, integrality_tolerance=1e-3):
         values = p.get_values(b, convert=bool, tolerance=integrality_tolerance)
         return [self._points[i] for (i,j) in values.items() if j]
 
+
 BIBD = BalancedIncompleteBlockDesign

src/sage/combinat/designs/database.py

@@ -296,6 +296,7 @@ def MOLS_18_3():
 #
 # This dictionary is used by designs.mutually_orthogonal_latin_squares(k,n).
 
+
 MOLS_constructions = {
     10 : (2, MOLS_10_2),
     12 : (5, MOLS_12_5),
@@ -2021,6 +2022,7 @@ def OA_10_1620():
 #
 # This dictionary is used by designs.orthogonal_array(k,n).
 
+
 OA_constructions = {
     18  : (7  , OA_7_18),
     40  : (9  , OA_9_40),
@@ -2455,6 +2457,7 @@ def QDM_57_9_1_1_8():
 #         }
 # }
 
+
 QDM: dict[tuple[int, int], dict] = {}
 for ((n,k,lmbda,mu,u),f) in [((19,6,1,1,1), QDM_19_6_1_1_1),
                              ((21,5,1,1,1), QDM_21_5_1_1_1),
@@ -4018,6 +4021,7 @@ def DM_993_32_1():
     G = AdditiveCyclic(993)
     return G, M
 
+
 DM = {
     (12 ,1) : (6 ,DM_12_6_1),
     (21 ,1) : (6 ,DM_21_6_1),
@@ -4686,6 +4690,7 @@ def BIBD_56_11_2():
     D = IncidenceStructure(libgap.Orbit(G, B, libgap.OnSets))
     return D._blocks
 
+
 # Index of the BIBD constructions
 #
 # Associates to triple (v,k,lambda) a function that return a

src/sage/combinat/designs/difference_family.py

@@ -3606,6 +3606,7 @@ def difference_family(v, k, l=1, existence=False, explain_construction=False, ch
 
     return G, D
 
+
 from sage.misc.rest_index_of_methods import gen_rest_table_index
 import sys
 __doc__ = __doc__.format(INDEX_OF_FUNCTIONS=gen_rest_table_index(sys.modules[__name__]))

src/sage/combinat/designs/ext_rep.py

@@ -565,6 +565,7 @@ def open_extrep_url(url):
     else:
         return f.read()
 
+
 pattern_integer = re.compile(r'\d+$')
 pattern_decimal = re.compile(r'-?\d+\.\d+$')
 pattern_rational = re.compile(r'-?\d+/\d+$')

src/sage/geometry/hyperplane_arrangement/library.py

@@ -802,4 +802,5 @@ def Shi(self, data, K=QQ, names=None, m=1):
         A.characteristic_polynomial.set_cache(charpoly)
         return A
 
+
 hyperplane_arrangements = HyperplaneArrangementLibrary()

src/sage/groups/abelian_gps/abelian_group.py

@@ -1880,5 +1880,6 @@ def gen(self, n):
         """
         return self._gens[n]
 
+
 # We allow subclasses to override this, analogous to Element
 AbelianGroup_class.Subgroup = AbelianGroup_subgroup

src/sage/groups/matrix_gps/morphism.py

@@ -42,6 +42,7 @@ def to_libgap(x):
         from sage.libs.gap.libgap import libgap
         return libgap(x)
 
+
 lazy_import('sage.groups.libgap_morphism', 'GroupMorphism_libgap',
             'MatrixGroupMorphism_im_gens', deprecation=25444)
 

src/sage/groups/perm_gps/cubegroup.py

@@ -295,6 +295,7 @@ def create_poly(face, color):
 
 ####################################################
 
+
 singmaster_indices = {
     1: "ulb",
     2: "ub",
@@ -1180,6 +1181,7 @@ def cubie_faces():
 
     return cubies
 
+
 cubie_face_list = cubie_faces()
 
 

src/sage/groups/perm_gps/permgroup.py

@@ -5087,6 +5087,7 @@ def is_normal(self, other=None):
             other = self.ambient_group()
         return PermutationGroup_generic.is_normal(self, other)
 
+
 # Allow for subclasses to use a different subgroup class
 PermutationGroup_generic.Subgroup = PermutationGroup_subgroup
 
@@ -5194,5 +5195,6 @@ def orbits(self):
         """
         return self._orbits
 
+
 from sage.misc.rest_index_of_methods import gen_rest_table_index
 __doc__ = __doc__.format(METHODS_OF_PermutationGroup_generic=gen_rest_table_index(PermutationGroup_generic))

src/sage/libs/pari/__init__.py

@@ -202,4 +202,5 @@ def _get_pari_instance():
 
     return P
 
+
 pari = _get_pari_instance()

src/sage/matrix/matrix_polynomial_dense.pyx

@@ -1670,8 +1670,8 @@ cdef class Matrix_polynomial_dense(Matrix_generic_dense):
         # the row-wise case (resp. column-wise case), it will be convenient to
         # have leading position ncols (resp. nrows) for these zero vectors
         pos_zero_vec = self.ncols() if row_wise else self.nrows()
-        leading_positions = [pos if pos>=0 else pos_zero_vec + 1 \
-                                         for pos in leading_positions]
+        leading_positions = [pos if pos >= 0 else pos_zero_vec + 1
+                             for pos in leading_positions]
         # leading positions should not have duplicates, which is equivalent to:
         # once sorted, it doesn't contain a pair of equal successive entries
         if not ordered:

src/sage/modular/arithgroup/congroup_gamma0.py

@@ -39,6 +39,7 @@ def is_Gamma0(x):
     """
     return isinstance(x, Gamma0_class)
 
+
 _gamma0_cache = {}
 def Gamma0_constructor(N):
     """

src/sage/modular/modform/constructor.py

@@ -134,6 +134,7 @@ def canonical_parameters(group, level, weight, base_ring):
     # forms spaces.
     return level, group, weight, base_ring
 
+
 _cache = {}
 
 def ModularForms_clear_cache():

src/sage/modular/pollack_stevens/distributions.py

@@ -224,6 +224,7 @@ def create_object(self, version, key):
         """
         return Symk_class(*key)
 
+
 OverconvergentDistributions = OverconvergentDistributions_factory('OverconvergentDistributions')
 Symk = Symk_factory('Symk')
 

src/sage/modular/pollack_stevens/fund_domain.py

@@ -56,6 +56,7 @@ def M2Z(x):
     x.set_immutable()
     return x
 
+
 Id = M2Z([1, 0, 0, 1])
 sig = M2Z([0, 1, -1, 0])
 tau = M2Z([0, -1, 1, -1])

src/sage/modular/pollack_stevens/sigma0.py

@@ -162,6 +162,7 @@ def create_object(self, version, key):
         """
         return Sigma0_class(*key)
 
+
 Sigma0 = Sigma0_factory('sage.modular.pollack_stevens.sigma0.Sigma0')
 
 

src/sage/modular/pollack_stevens/space.py

@@ -189,6 +189,7 @@ def create_object(self, version, key):
         """
         return PollackStevensModularSymbolspace(*key)
 
+
 PollackStevensModularSymbols = PollackStevensModularSymbols_factory('PollackStevensModularSymbols')
 
 

src/sage/modules/fg_pid/fgp_morphism.py

@@ -453,6 +453,7 @@ def lift(self, x):
         assert self(y) == x, "bug in phi.lift()"
         return y
 
+
 from sage.categories.homset import Homset
 
 import sage.misc.weak_dict

src/sage/plot/plot3d/plot3d.py

@@ -953,6 +953,7 @@ def smooth_triangle(self, a, b, c, da, db, dc, color=None):
         """
         return [a,b,c]
 
+
 from . import parametric_plot3d
 def plot3d(f, urange, vrange, adaptive=False, transformation=None, **kwds):
     """

src/sage/schemes/elliptic_curves/cm.py

@@ -535,6 +535,7 @@ def cm_orders(h, proof=None):
 # quadratic field with class number h, and n is the number of such
 # fields.  These are all *unconditional* (not dependent on GRH).
 
+
 watkins_table = {1: (163, 9), 2: (427, 18), 3: (907, 16), 4: (1555, 54), 5: (2683, 25),
                  6: (3763, 51), 7: (5923, 31), 8: (6307, 131), 9: (10627, 34), 10:
                  (13843, 87), 11: (15667, 41), 12: (17803, 206), 13: (20563, 37), 14:
@@ -717,6 +718,7 @@ class number `h` is also the largest discriminant, but this is not
 # initialise it with h=1 only; other values will be added by calls to
 # discriminants_with_bounded_class_number().
 
+
 hDf_dict = {ZZ(1): [(ZZ(D), ZZ(h)) for D,h in
                     [(-3, 1), (-3, 2), (-3, 3), (-4, 1), (-4, 2), (-7, 1), (-7, 2),
                      (-8, 1), (-11, 1), (-19, 1), (-43, 1), (-67, 1), (-163, 1)]]}

src/sage/schemes/elliptic_curves/ell_curve_isogeny.py

@@ -171,6 +171,7 @@ def _isogeny_determine_algorithm(E, kernel):
 
     raise ValueError("invalid parameters to EllipticCurveIsogeny constructor")
 
+
 from sage.misc.superseded import deprecated_function_alias
 isogeny_determine_algorithm = deprecated_function_alias(33619, _isogeny_determine_algorithm)
 
@@ -3451,6 +3452,7 @@ def compute_isogeny_stark(E1, E2, ell):
     qn /= qn.leading_coefficient()
     return qn
 
+
 from sage.misc.superseded import deprecated_function_alias
 compute_isogeny_starks = deprecated_function_alias(34871, compute_isogeny_stark)
 

src/sage/schemes/elliptic_curves/ell_finite_field.py

@@ -2127,6 +2127,7 @@ def curves_with_j_0_char3(K):
 
 # dict to hold precomputed coefficient vectors of supersingular j values (excluding 0, 1728):
 
+
 supersingular_j_polynomials = {}
 
 def fill_ss_j_dict():

src/sage_docbuild/__main__.py

@@ -498,5 +498,6 @@ def excepthook(*exc_info):
     builder = getattr(get_builder(name), typ)
     builder()
 
+
 if __name__ == '__main__':
     sys.exit(main())

src/sage_docbuild/conf.py

@@ -691,6 +691,7 @@ def add_page_context(app, pagename, templatename, context, doctree):
         context['reference_root'] = os.path.join(relpath, 'index.html')
         context['refsub'] = True
 
+
 dangling_debug = False
 
 def debug_inf(app, message):
@@ -816,6 +817,7 @@ def find_sage_dangling_links(app, env, node, contnode):
     newnode.append(contnode)
     return newnode
 
+
 # lists of basic Python class which are documented as functions
 base_class_as_func = [
     'bool', 'complex', 'dict', 'file', 'float',
@@ -842,6 +844,7 @@ def nitpick_patch_config(app):
     app.config.values['nitpicky'] = (False, 'sage')
     app.config.values['nitpick_ignore'] = ([], 'sage')
 
+
 skip_picklability_check_modules = [
     #'sage.misc.test_nested_class', # for test only
     'sage.misc.latex',

src/sage_docbuild/ext/sage_autodoc.py

@@ -73,6 +73,7 @@ def getdoc(obj, *args, **kwargs):
     return sage_getdoc_original(obj)
 # ------------------------------------------------------------------
 
+
 if TYPE_CHECKING:
     from sphinx.ext.autodoc.directive import DocumenterBridge
 

src/sage_setup/autogen/interpreters/storage.py

@@ -440,6 +440,7 @@ class StorageTypeSimple(StorageTypeAssignable):
     """
     pass
 
+
 ty_int = StorageTypeSimple('int')
 ty_double = StorageTypeSimple('double')
 
@@ -461,6 +462,7 @@ def assign_c_from_py(self, c, py):
         """
         return je("{{ c }} = CDE_to_dz({{ py }})", c=c, py=py)
 
+
 ty_double_complex = StorageTypeDoubleComplex('double_complex')
 
 
@@ -650,6 +652,7 @@ def cython_clear(self, loc):
         """
         return je("Py_CLEAR({{ loc }})", loc=loc)
 
+
 ty_python = StorageTypePython()
 
 
@@ -846,6 +849,7 @@ def assign_c_from_py(self, c, py):
             mpfr_set({{ c }}, rn.value, MPFR_RNDN)"""),
             myself=self, c=c, py=py)
 
+
 ty_mpfr = StorageTypeMPFR()
 
 class StorageTypeMPC(StorageTypeAutoReference):
@@ -948,4 +952,5 @@ def assign_c_from_py(self, c, py):
 cn{{ myself.id }} = self.domain({{ py }})
 mpc_set_fr_fr({{ c }}, cn.__re, cn.__im, MPC_RNDNN)""", myself=self, c=c, py=py)
 
+
 ty_mpc = StorageTypeMPC()

src/tox.ini

@@ -109,6 +109,7 @@ description =
     # E111: indentation is not a multiple of four
     # E211: whitespace before '('
     # E271: multiple spaces after keyword
+    # E305: expected 2 blank lines after class or function definition, found 1
     # E306: expected 1 blank line before a nested definition, found 0
     # E401: multiple imports on one line
     # E502 the backslash is redundant between brackets
@@ -126,8 +127,8 @@ description =
     # W605: invalid escape sequence ‘x’
     # See https://pycodestyle.pycqa.org/en/latest/intro.html#error-codes
 deps = pycodestyle
-commands = pycodestyle --select E111,E21,E222,E227,E25,E271,E303,E306,E401,E502,E701,E702,E703,E71,E72,W291,W293,W391,W605 {posargs:{toxinidir}/sage/}
-       pycodestyle --select E111,E271,E301,E306,E401,E703,E712,E713,E714,E72,W29,W391,W605, --filename *.pyx {posargs:{toxinidir}/sage/}
+commands = pycodestyle --select E111,E21,E222,E227,E25,E271,E303,E305,E306,E401,E502,E701,E702,E703,E71,E72,W291,W293,W391,W605 {posargs:{toxinidir}/sage/}
+       pycodestyle --select E111,E271,E301,E306,E401,E502,E703,E712,E713,E714,E72,W29,W391,W605, --filename *.pyx {posargs:{toxinidir}/sage/}
 
 [pycodestyle]
 max-line-length = 160