code: def strip_masked(fasta, min_len, print_masked):
      
      for seq in parse_fasta(fasta):
          nm, masked = parse_masked(seq, min_len)
          nm = ['%s removed_masked >=%s' % (seq[0], min_len), ''.join(nm)]
          yield [0, nm]
          if print_masked is True:
              for i, m in enumerate([i for i in masked if i != []], 1):
                  m = ['%s insertion:%s' % (seq[0], i), ''.join(m)]
                  yield [1, m]
docs: remove masked regions from fasta file as long as
      they are longer than min_len