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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 _new_token(self, chars=None, line_no=None):
 """ Appends new token to token stream. `chars` List of token characters. Defaults to current token list. `line_no` Line number for token. Defaults to current line number. """


        if not line_no:
            line_no = self._line_no

        if not chars:
            chars = self._token_chars

        if chars:
            # add new token
            self._tokens.append((line_no, ''.join(chars)))
            self._token_chars = []