code: def _replace_locals(tok):
      
      toknum, tokval = tok
      if toknum == tokenize.OP and tokval == '@':
          return tokenize.OP, _LOCAL_TAG
      return toknum, tokval
docs: Replace local variables with a syntactically valid name.
  
      Parameters
      ----------
      tok : tuple of int, str
          ints correspond to the all caps constants in the tokenize module
  
      Returns
      -------
      t : tuple of int, str
          Either the input or token or the replacement values
  
      Notes
      -----
      This is somewhat of a hack in that we rewrite a string such as ``'@a'`` as
      ``'__pd_eval_local_a'`` by telling the tokenizer that ``__pd_eval_local_``
      is a ``tokenize.OP`` and to replace the ``'@'`` symbol with it.