Trac #33536: Some changes suggested by lgtm

Namely, caution about arguments with default value `{}`.

URL: https://trac.sagemath.org/33536
Reported by: chapoton
Ticket author(s): Frédéric Chapoton
Reviewer(s): Kwankyu Lee

src/sage/combinat/designs/bibd.py

@@ -840,7 +840,8 @@ def v_4_1_BIBD(v, check=True):
 
  return bibd
 
-def BIBD_from_PBD(PBD,v,k,check=True,base_cases={}):
+
+def BIBD_from_PBD(PBD, v, k, check=True, base_cases=None):
  r"""
  Return a `(v,k,1)`-BIBD from a `(r,K)`-PBD where `r=(v-1)/(k-1)`.
 
@@ -868,6 +869,8 @@ def BIBD_from_PBD(PBD,v,k,check=True,base_cases={}):
  sage: PBD = PBD_4_5_8_9_12(17)
  sage: bibd = is_pairwise_balanced_design(BIBD_from_PBD(PBD,52,4),52,[4])
  """
+ if base_cases is None:
+ base_cases = {}
  r = (v-1) // (k-1)
  bibd = []
  for X in PBD:

src/sage/quivers/representation.py

@@ -1522,7 +1522,7 @@ def __truediv__(self, sub):
  """
  return self.quotient(sub)
 
- def _submodule(self, spaces={}):
+ def _submodule(self, spaces=None):
  """
  Return the submodule specified by the data.
 
@@ -1552,7 +1552,8 @@ def _submodule(self, spaces={}):
  sage: M.submodule(M.gens()) is M # indirect doctest
  True
  """
-
+ if spaces is None:
+ spaces = {}
  # Add zero submodules
  for v in self._quiver:
  if v not in spaces:

src/sage/rings/fraction_field.py

@@ -904,7 +904,7 @@ def some_elements(self):
  for a in self._R.some_elements():
  for b in self._R.some_elements():
  if a != b and self(a) and self(b):
- ret.append(self(a)/self(b))
+ ret.append(self(a) / self(b))
  return ret
 
  def _gcd_univariate_polynomial(self, f, g):
@@ -945,6 +945,7 @@ def _gcd_univariate_polynomial(self, f, g):
  g1 = Num(g.numerator())
  return Pol(f1.gcd(g1)).monic()
 
+
 class FractionField_1poly_field(FractionField_generic):
  """
  The fraction field of a univariate polynomial ring over a field.
@@ -1065,7 +1066,6 @@ def _coerce_map_from_(self, R):
  return super(FractionField_1poly_field, self)._coerce_map_from_(R)
 
 
-
 class FractionFieldEmbedding(DefaultConvertMap_unique):
  r"""
  The embedding of an integral domain into its field of fractions.
@@ -1256,7 +1256,7 @@ def _call_(self, x, check=True):
 
  def _call_with_args(self, x, args=(), kwds={}):
  r"""
- Evaluation this map at ``x``.
+ Evaluate this map at ``x``.
 
  INPUT:
 
@@ -1268,10 +1268,9 @@ def _call_with_args(self, x, args=(), kwds={}):
  sage: K = R.fraction_field()
  sage: R(K.gen(), check=True)
  x
-
  """
- check = kwds.pop('check', True)
- if args or kwds:
+ check = kwds.get('check', True)
+ if args or any(key != 'check' for key in kwds):
  raise NotImplementedError("__call__ cannot be called with additional arguments other than check=True/False")
  return self._call_(x, check=check)