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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 _get_num_tokens_from_first_line(line: str) -> Optional[int]: """ This function takes in input a string and if it contains 1 or 2 integers, it assumes the largest one it the number of tokens. Returns None if the line doesn't match that pattern. """

        fields = line.split(' ')
        if 1 <= len(fields) <= 2:
            try:
                int_fields = [int(x) for x in fields]
            except ValueError:
                return None
            else:
                num_tokens = max(int_fields)
                logger.info('Recognized a header line in the embedding file with number of tokens: %d',
                            num_tokens)
                return num_tokens
        return None