code: def make_charsets(self):
          
          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
docs: Override this function for Phylip dataset as the content is different and
          goes into a separate file.