Fix docstring errors

pandas/core/generic.py

@@ -530,7 +530,7 @@ def set_axis(self, labels, axis=0, inplace=None):
  The axis to update. The value 0 identifies the rows, and 1
  identifies the columns.
 
- inplace : boolean, default None
+ inplace : bool, default None
  Whether to return a new %(klass)s instance.
 
  .. warning::
@@ -3989,7 +3989,8 @@ def sort_values(self, by=None, axis=0, ascending=True, inplace=False,
 
  Returns
  -------
- sorted_obj : %(klass)s
+ sorted_obj : %(klass)s or None
+ An object of same type as caller if inplace=False, None otherwise.
 
  Examples
  --------
@@ -4061,7 +4062,9 @@ def sort_index(self, axis=0, level=None, ascending=True, inplace=False,
 
  Parameters
  ----------
- axis : %(axes)s to direct sorting
+ axis : {0 or 'index', 1 or 'columns'}, default 0
+ The axis along which to sort. The value 0 identifies the rows,
+ and 1 identifies the columns.
  level : int or level name or list of ints or list of level names
  If not None, sort on values in specified index level(s).
  ascending : bool, default True
@@ -4082,7 +4085,8 @@ def sort_index(self, axis=0, level=None, ascending=True, inplace=False,
 
  Returns
  -------
- sorted_obj : %(klass)s
+ sorted_obj : %(klass)s or None
+ An object of same type as caller if inplace=False, None otherwise.
  """
  inplace = validate_bool_kwarg(inplace, 'inplace')
  axis = self._get_axis_number(axis)