def sentence_bytes(self, sentence):
        """ Return bytes of a sentence.
        This is a very simple parser. Sentence is a list of strings and numbers.
        1st element of sentence MUST match a token.
        """
        result = [TOKENS[sentence[0]]]

        for i in sentence[1:]:  # Remaining bytes
            if isinstance(i, str):
                result.extend(self.literal(i))
            elif isinstance(i, float) or isinstance(i, int):  # A number?
                result.extend(self.number(i))
            else:
                result.extend(i)  # Must be another thing

        return result
Return bytes of a sentence.
        This is a very simple parser. Sentence is a list of strings and numbers.
        1st element of sentence MUST match a token.