code: def fasta(self):
          
          max_line_length = 79
          fasta_str = '>{0}:{1}|PDBID|CHAIN|SEQUENCE\n'.format(
              self.parent.id.upper(), self.id)
          seq = self.sequence
          split_seq = [seq[i: i + max_line_length]
                       for i in range(0, len(seq), max_line_length)]
          for seq_part in split_seq:
              fasta_str += '{0}\n'.format(seq_part)
          return fasta_str
docs: Generates sequence data for the protein in FASTA format.