def make_charsets(self):
        """
        Override this function for Phylip dataset as the content is different and
        goes into a separate file.
        """
        count_start = 1
        out = ''
        for gene_code, lengths in self.data.gene_codes_and_lengths.items():
            count_end = lengths[0] + count_start - 1
            out += self.format_charset_line(gene_code, count_start, count_end)
            count_start = count_end + 1
        return out
Override this function for Phylip dataset as the content is different and
        goes into a separate file.