code: def compare_seqs(seqs):
      
      A, B, ignore_gaps = seqs
      a, b = A[1], B[1] # actual sequences
      if len(a) != len(b):
          print('# reads are not the same length', file=sys.stderr)
          exit()
      if ignore_gaps is True:
          pident = calc_pident_ignore_gaps(a, b)
      else:
          pident = calc_pident(a, b)
      return A[0], B[0], pident
docs: compare pairs of sequences