def _rewrite_assign(tok):
toknum, tokval = tok<EOL>return toknum, '<STR_LIT>' if tokval == '<STR_LIT:=>' else tokval<EOL>
Rewrite the assignment operator for PyTables expressions that use ``=``
    as a substitute for ``==``.

    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