code: def _check_for_default_values(fname, arg_val_dict, compat_args):
      
      for key in arg_val_dict:
          # try checking equality directly with '=' operator,
          # as comparison may have been overridden for the left
          # hand object
          try:
              v1 = arg_val_dict[key]
              v2 = compat_args[key]
  
              # check for None-ness otherwise we could end up
              # comparing a numpy array vs None
              if (v1 is not None and v2 is None) or \
                 (v1 is None and v2 is not None):
                  match = False
              else:
                  match = (v1 == v2)
  
              if not is_bool(match):
                  raise ValueError("'match' is not a boolean")
  
          # could not compare them directly, so try comparison
          # using the 'is' operator
          except ValueError:
              match = (arg_val_dict[key] is compat_args[key])
  
          if not match:
              raise ValueError(("the '{arg}' parameter is not "
                                "supported in the pandas "
                                "implementation of {fname}()".
                                format(fname=fname, arg=key)))
docs: Check that the keys in `arg_val_dict` are mapped to their
      default values as specified in `compat_args`.
  
      Note that this function is to be called only when it has been
      checked that arg_val_dict.keys() is a subset of compat_args