use Parent in QQ

Author: fchapoton

src/sage/rings/rational_field.py

@@ -62,7 +62,7 @@
 import sage.rings.number_field.number_field_base as number_field_base
 from sage.misc.fast_methods import Singleton
 from sage.misc.superseded import deprecated_function_alias
-from sage.structure.parent_gens import ParentWithGens
+from sage.structure.parent import Parent
 from sage.structure.sequence import Sequence
 
 
@@ -235,8 +235,9 @@ def __init__(self):
         """
         from sage.categories.basic import QuotientFields
         from sage.categories.number_fields import NumberFields
-        ParentWithGens.__init__(self, self, category=[QuotientFields().Metric(),
-                                                      NumberFields()])
+        Parent.__init__(self, base=self,
+                        category=[QuotientFields().Metric(),
+                                  NumberFields()])
         self._assign_names(('x',), normalize=False)  # ?????
         self._populate_coercion_lists_(init_no_parent=True)
 
@@ -862,7 +863,7 @@ def hilbert_symbol_negative_at_S(self, S, b, check=True):
             if p != infty:
                 if check and not is_prime(p):
                     raise ValueError("all entries in list must be prime"
-                                    " or -1 for infinite place")
+                                     " or -1 for infinite place")
                 R = Qp(p)
                 if R(b).is_square():
                     raise ValueError("second argument must be a nonsquare with"
@@ -1055,7 +1056,7 @@ def power_basis(self):
             sage: QQ.power_basis()
             [1]
         """
-        return [ self.gen() ]
+        return [self.gen()]
 
     def extension(self, poly, names, **kwds):
         r"""
@@ -1133,7 +1134,7 @@ def _an_element_(self):
             sage: QQ.an_element() # indirect doctest
             1/2
         """
-        return Rational((1,2))
+        return Rational((1, 2))
 
     def some_elements(self):
         r"""
@@ -1247,7 +1248,7 @@ def random_element(self, num_bound=None, den_bound=None, *args, **kwds):
             den = ZZ.random_element(1, den_bound+1, *args, **kwds)
             while den == 0:
                 den = ZZ.random_element(1, den_bound+1, *args, **kwds)
-            return self((num,den))
+            return self((num, den))
 
     def zeta(self, n=2):
         """
@@ -1381,7 +1382,7 @@ def selmer_group_iterator(self, S, m, proof=True):
 
         from sage.misc.misc_c import prod
         for ev in product(*[range(o) for o in ords]):
-            yield prod((p**e for p,e in zip(KSgens, ev)), one)
+            yield prod((p**e for p, e in zip(KSgens, ev)), one)
 
     def selmer_space(self, S, p, proof=None):
         r"""
@@ -1520,7 +1521,7 @@ def quadratic_defect(self, a, p, check=True):
                 return v + 1
 
     #################################
-    ## Coercions to interfaces
+    #  Coercions to interfaces
     #################################
     def _gap_init_(self):
         r"""
@@ -1663,7 +1664,7 @@ def _factor_univariate_polynomial(self, f):
         G = list(f._pari_with_name().factor())
 
         # normalize the leading coefficients
-        F = [(f.parent()(g).monic(), int(e)) for (g,e) in zip(*G)]
+        F = [(f.parent()(g).monic(), int(e)) for (g, e) in zip(*G)]
 
         from sage.structure.factorization import Factorization
         return Factorization(F, f.leading_coefficient())