docs: def problem_with_codon(codon_index, codon_list, bad_seqs):
      """
      Return true if the given codon overlaps with a bad sequence.
      """
  
      base_1 = 3 * codon_index
      base_3 = 3 * codon_index + 2
  
      gene_seq = ''.join(codon_list)
  
      for bad_seq in bad_seqs:
          problem = bad_seq.search(gene_seq)
          if problem and problem.start() < base_3 and problem.end() > base_1:
              return True
  
      return False