gh-35206: fixing some E502 (unnecessary backslash) in pyx files

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### 📚 Description

This removes most instances of pycodestyle warning

E502 the backslash is redundant between brackets

inside pyx files. There remains only a few in rings/, that could be
easily fixed when activiting the check in the linter.

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URL: #35206
Reported by: Frédéric Chapoton
Reviewer(s): David Coudert

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=0ea92e19072c843aa21527e051eff0a0f97eb9ad
-md5=44e659f4d263acad8194e16952762a82
-cksum=3343113057
+sha1=9dc473ec70c91a061179259f66a2010eaa89c81c
+md5=bf9729a5443b7ddd19ade63af2d3bf53
+cksum=1529922696

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-49c2cd323e638cdfb0444d72daad21b4ddbd1887
+892c702f48724208e34e8e01f97e8989e4143463

src/sage/groups/perm_gps/partn_ref/automorphism_group_canonical_label.pyx

@@ -393,9 +393,10 @@ cdef void deallocate_agcl_work_space(agcl_work_space *work_space):
 cdef aut_gp_and_can_lab *get_aut_gp_and_can_lab(void *S,
     PartitionStack *partition, int n,
     bint (*all_children_are_equivalent)(PartitionStack *PS, void *S),
-    int (*refine_and_return_invariant)\
-         (PartitionStack *PS, void *S, int *cells_to_refine_by, int ctrb_len),
-    int (*compare_structures)(int *gamma_1, int *gamma_2, void *S1, void *S2, int degree),
+    int (*refine_and_return_invariant)(PartitionStack *PS, void *S,
+                                       int *cells_to_refine_by, int ctrb_len),
+    int (*compare_structures)(int *gamma_1, int *gamma_2, void *S1, void *S2,
+                              int degree),
     bint canonical_label, StabilizerChain *input_group,
     agcl_work_space *work_space_prealloc, aut_gp_and_can_lab *output_prealloc) except NULL:
     """

src/sage/groups/perm_gps/partn_ref/canonical_augmentation.pyx

@@ -380,11 +380,13 @@ cdef void deallocate_cgd(canonical_generator_data *cgd):
     sig_free(cgd.parent_stack)
     sig_free(cgd)
 
+
 cdef iterator *setup_canonical_generator(int degree,
     bint (*all_children_are_equivalent)(PartitionStack *PS, void *S),
-    int (*refine_and_return_invariant)\
-         (PartitionStack *PS, void *S, int *cells_to_refine_by, int ctrb_len),
-    int (*compare_structures)(int *gamma_1, int *gamma_2, void *S1, void *S2, int degree),
+    int (*refine_and_return_invariant)(PartitionStack *PS, void *S,
+                                       int *cells_to_refine_by, int ctrb_len),
+    int (*compare_structures)(int *gamma_1, int *gamma_2, void *S1, void *S2,
+                              int degree),
     int (*generate_children)(void *, aut_gp_and_can_lab *, iterator *),
     void *(*apply_augmentation)(void *, void *, void *, int *, bint *),
     void (*free_object)(void *),

src/sage/groups/perm_gps/partn_ref/double_coset.pyx

@@ -268,9 +268,10 @@ cdef void deallocate_dc_work_space(dc_work_space *work_space):
 
 cdef int double_coset(void *S1, void *S2, PartitionStack *partition1, int *ordering2,
     int n, bint (*all_children_are_equivalent)(PartitionStack *PS, void *S),
-    int (*refine_and_return_invariant)\
-         (PartitionStack *PS, void *S, int *cells_to_refine_by, int ctrb_len),
-    int (*compare_structures)(int *gamma_1, int *gamma_2, void *S1, void *S2, int degree),
+    int (*refine_and_return_invariant)(PartitionStack *PS, void *S,
+                                       int *cells_to_refine_by, int ctrb_len),
+    int (*compare_structures)(int *gamma_1, int *gamma_2, void *S1, void *S2,
+                              int degree),
     StabilizerChain *input_group,
     dc_work_space *work_space_prealloc, int *isom) except -1:
     """

src/sage/libs/mpmath/ext_impl.pyx

@@ -1847,8 +1847,8 @@ cdef MPF_complex_pow_int(MPF *zre, MPF *zim, MPF *xre, MPF *xim, mpz_t n, MPopts
     xret = MPF_to_tuple(xre)
     ximt = MPF_to_tuple(xim)
     from mpmath.libmp import mpc_pow_int
-    vr, vi = mpc_pow_int((xret, ximt), mpzi(n), \
-        opts.prec, rndmode_to_python(opts.rounding))
+    vr, vi = mpc_pow_int((xret, ximt), mpzi(n),
+                         opts.prec, rndmode_to_python(opts.rounding))
     MPF_set_tuple(zre, vr)
     MPF_set_tuple(zim, vi)
 
@@ -1892,8 +1892,8 @@ cdef MPF_complex_pow_re(MPF *zre, MPF *zim, MPF *xre, MPF *xim, MPF *y, MPopts o
     ximt = MPF_to_tuple(xim)
     yret = MPF_to_tuple(y)
     from mpmath.libmp import mpc_pow_mpf, fzero
-    vr, vi = mpc_pow_mpf((xret, ximt), yret, \
-        opts.prec, rndmode_to_python(opts.rounding))
+    vr, vi = mpc_pow_mpf((xret, ximt), yret,
+                         opts.prec, rndmode_to_python(opts.rounding))
     MPF_set_tuple(zre, vr)
     MPF_set_tuple(zim, vi)
 
@@ -1910,8 +1910,8 @@ cdef MPF_complex_pow(MPF *zre, MPF *zim, MPF *xre, MPF *xim, MPF *yre, MPF *yim,
     yret = MPF_to_tuple(yre)
     yimt = MPF_to_tuple(yim)
     from mpmath.libmp import mpc_pow
-    vr, vi = mpc_pow((xret,ximt), (yret,yimt), \
-        opts.prec, rndmode_to_python(opts.rounding))
+    vr, vi = mpc_pow((xret, ximt), (yret, yimt),
+                     opts.prec, rndmode_to_python(opts.rounding))
     MPF_set_tuple(zre, vr)
     MPF_set_tuple(zim, vi)
 

src/sage/libs/mpmath/ext_main.pyx

@@ -2602,13 +2602,15 @@ def hypsum_internal(int p, int q, param_types, str ztype, coeffs, z,
         sage: print(mp.hyp1f1(1,2,3))
         6.36184564106256
 
-    TODO: convert mpf/mpc parameters to fixed-point numbers here
-    instead of converting to tuples within MPF_hypsum.
+    .. TODO::
+
+        convert mpf/mpc parameters to fixed-point numbers here
+        instead of converting to tuples within MPF_hypsum.
     """
     cdef mpf f
     cdef mpc c
     c = mpc.__new__(mpc)
-    have_complex, magn = MPF_hypsum(&c.re, &c.im, p, q, param_types, \
+    have_complex, magn = MPF_hypsum(&c.re, &c.im, p, q, param_types,
         ztype, coeffs, z, prec, wp, epsshift, magnitude_check, kwargs)
     if have_complex:
         v = c

src/sage/libs/mpmath/utils.pyx

@@ -128,7 +128,7 @@ cpdef normalize(long sign, Integer man, exp, long bc, long prec, str rnd):
     res = PY_NEW(Integer)
     if shift > 0:
         if rnd == 'n':
-            if mpz_tstbit(man.value, shift-1) and (mpz_tstbit(man.value, shift)\
+            if mpz_tstbit(man.value, shift-1) and (mpz_tstbit(man.value, shift)
                 or (mpz_scan1(man.value, 0) < (shift-1))):
                 mpz_cdiv_q_2exp(res.value, man.value, shift)
             else:

src/sage/libs/ntl/ntl_ZZ.pyx

@@ -93,8 +93,8 @@ cdef class ntl_ZZ():
             v = str(v)
             if not v:
                 v = '0'
-            if not ((v[0].isdigit() or v[0] == '-') and \
-                    (v[1:-1].isdigit() or (len(v) <= 2)) and \
+            if not ((v[0].isdigit() or v[0] == '-') and
+                    (v[1:-1].isdigit() or (len(v) <= 2)) and
                     (v[-1].isdigit() or (v[-1].lower() in ['l','r']))):
                 raise ValueError("invalid integer: %s" % v)
             ccreadstr(self.x, v)

src/sage/rings/complex_mpc.pyx

@@ -313,8 +313,8 @@ cdef class MPComplexField_class(sage.rings.ring.Field):
         try:
             n = _mpc_rounding_modes.index(rnd)
         except ValueError:
-            raise ValueError("rnd (=%s) must be of the form RNDxy"\
-                "where x and y are one of N, Z, U, D" % rnd)
+            raise ValueError("rnd (=%s) must be of the form RNDxy"
+                             "where x and y are one of N, Z, U, D" % rnd)
         self.__rnd = n
         self.__rnd_str = rnd
 
@@ -1158,8 +1158,8 @@ cdef class MPComplexNumber(sage.structure.element.FieldElement):
             TypeError: can...t convert complex to float; use abs(z)
         """
         if mpfr_zero_p(self.value.im):
-            return mpfr_get_d(self.value.re,\
-                                   rnd_re((<MPComplexField_class>self._parent).__rnd))
+            return mpfr_get_d(self.value.re,
+                              rnd_re((<MPComplexField_class>self._parent).__rnd))
         else:
             raise TypeError("can't convert complex to float; use abs(z)")
 

src/sage/rings/finite_rings/integer_mod.pyx

@@ -779,14 +779,14 @@ cdef class IntegerMod_abstract(FiniteRingElement):
             na = a_red.multiplicative_order()
             nb = b_red.multiplicative_order()
             if not na.divides(nb):  # cannot be a power
-                raise ValueError(f"no logarithm of {self} found to base {b} modulo {self.modulus()}" \
+                raise ValueError(f"no logarithm of {self} found to base {b} modulo {self.modulus()}"
                               + (f" (no solution modulo {q})" if q != self.modulus() else ""))
 
             if p == 2 and e >= 3:   # (ZZ/2^e)* is not cyclic; must not give unsolvable DLPs to Pari
                 try:
                     v = discrete_log(a_red, b_red, nb)
                 except ValueError:
-                    raise ValueError(f"no logarithm of {self} found to base {b} modulo {self.modulus()}" \
+                    raise ValueError(f"no logarithm of {self} found to base {b} modulo {self.modulus()}"
                                   + (f" (no solution modulo {q})" if q != self.modulus() else ""))
             else:
                 try:

src/sage/rings/finite_rings/residue_field.pyx

@@ -1579,8 +1579,8 @@ class ResidueFiniteField_prime_modn(ResidueField_generic, FiniteField_prime_modn
             self._populate_coercion_lists_(coerce_list=coerce_list, convert_list=[ReductionMap(K, self, None, None, None, None)]) # could be special-cased a bit more.
         else:
             PBinv = PB**(-1)
-            self._populate_coercion_lists_(coerce_list=[IntegerMod_to_IntegerMod(GF(intp), self), Integer_to_IntegerMod(self), Int_to_IntegerMod(self), ResidueFieldHomomorphism_global(OK, self, to_vs, to_order, PB, PBinv)], \
-                                                 convert_list=[ReductionMap(K, self, to_vs, to_order, PB, PBinv)])
+            self._populate_coercion_lists_(coerce_list=[IntegerMod_to_IntegerMod(GF(intp), self), Integer_to_IntegerMod(self), Int_to_IntegerMod(self), ResidueFieldHomomorphism_global(OK, self, to_vs, to_order, PB, PBinv)],
+                                           convert_list=[ReductionMap(K, self, to_vs, to_order, PB, PBinv)])
 
     def _element_constructor_(self, x):
         """

src/sage/rings/morphism.pyx

@@ -2035,8 +2035,8 @@ cdef class RingHomomorphism_im_gens(RingHomomorphism):
         """
         D = self.domain()
         ig = self._im_gens
-        s = '\n'.join(['%s |--> %s'%(D.gen(i), ig[i]) for\
-                       i in range(D.ngens())])
+        s = '\n'.join('{} |--> {}'.format(D.gen(i), ig[i])
+                       for i in range(D.ngens()))
         if s and self._base_map is not None:
             s += '\nwith map of base ring'
         return s
@@ -2866,21 +2866,22 @@ cdef class RingHomomorphism_from_quotient(RingHomomorphism):
         """
         return hash(self.phi)
 
-    def _repr_defn(self):
+    def _repr_defn(self) -> str:
         """
         Used internally for printing this function.
 
         EXAMPLES::
 
-            sage: R.<x,y> = QQ[]; S.<xx,yy> = R.quo([x^2,y^2]); f = S.hom([yy,xx])
+            sage: R.<x,y> = QQ[]; S.<xx,yy> = R.quo([x^2,y^2])
+            sage: f = S.hom([yy,xx])
             sage: print(f._repr_defn())
             xx |--> yy
             yy |--> xx
         """
         D = self.domain()
         ig = self.phi.im_gens()
-        return '\n'.join(['%s |--> %s'%(D.gen(i), ig[i]) for\
-                          i in range(D.ngens())])
+        return '\n'.join('{} |--> {}'.format(D.gen(i), ig[i])
+                         for i in range(D.ngens()))
 
     cpdef Element _call_(self, x):
         """

src/sage/rings/padics/padic_printing.pyx

@@ -483,18 +483,17 @@ cdef class pAdicPrinter_class(SageObject):
             sage: P._sep()
             '&'
         """
-
-        return pAdicPrinter, (self.ring, \
-                              {'mode': self._print_mode(), \
-                               'pos': self.pos, \
-                               'ram_name': self.ram_name, \
-                               'unram_name': self.unram_name, \
-                               'var_name': self.var_name, \
-                               'max_ram_terms': self.max_ram_terms, \
-                               'max_unram_terms': self.max_unram_terms, \
-                               'max_terse_terms': self.max_terse_terms, \
-                               'sep':self.sep, \
-                               'alphabet': self.alphabet, \
+        return pAdicPrinter, (self.ring,
+                              {'mode': self._print_mode(),
+                               'pos': self.pos,
+                               'ram_name': self.ram_name,
+                               'unram_name': self.unram_name,
+                               'var_name': self.var_name,
+                               'max_ram_terms': self.max_ram_terms,
+                               'max_unram_terms': self.max_unram_terms,
+                               'max_terse_terms': self.max_terse_terms,
+                               'sep':self.sep,
+                               'alphabet': self.alphabet,
                                'show_prec': self.show_prec})
 
     def __richcmp__(self, other, op):