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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 token_handler_str_default( token, dispatcher, node, subnode, sourcepath_stack=(None,)):
 """ Standard token handler that will return the value, ignoring any tokens or strings that have been remapped. """


    if isinstance(token.pos, int):
        _, lineno, colno = node.getpos(subnode, token.pos)
    else:
        lineno, colno = None, None
    yield StreamFragment(subnode, lineno, colno, None, sourcepath_stack[-1])