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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _replace_locals(tok):
 """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. """

    toknum, tokval = tok
    if toknum == tokenize.OP and tokval == '@':
        return tokenize.OP, _LOCAL_TAG
    return toknum, tokval