code: def reformat(found_sequences):
      '''Truncate the FASTA headers so that the first field is a 4-character ID.'''
      for (pdb_id, chain, file_name), sequence in sorted(found_sequences.iteritems()):
          header = sequence[0]
          assert(header[0] == '>')
          tokens = header.split('|')
          tokens[0] = tokens[0][:5]
          assert(len(tokens[0]) == 5)
          sequence[0] = "|".join(tokensf reformat(found_sequences):
      '''Truncate the FASTA headers so that the first field is a 4-character ID.'''
      for (pdb_id, chain, file_name), sequence in sorted(found_sequences.iteritems()):
          header = sequence[0]
          assert(header[0] == '>')
          tokens = header.split('|')
          tokens[0] = tokens[0][:5]
          assert(len(tokens[0]) == 5)
          sequence[0] = "|".join(tokens)
docs: Truncate the FASTA headers so that the first field is a 4-character ID.