docs: def dePrefixAndSuffixFasta(sequences):
      """
      sequences: an iterator producing Bio.Seq sequences.
  
      return: a generator of sequences with no duplicates and no fully contained
          subsequences.
      """
      sequences = sorted(sequences, key=lambda s: len(s.seq), reverse=True)
      seen = set()
      for s in sequences:
          thisSeq = str(s.seq)
          thisHash = md5(thisSeq.encode('UTF-8')).digest()
          if thisHash not in seen:
              # Add prefixes.
              newHash = md5()
              for nucl in thisSeq:
                  newHash.update(nucl.encode('UTF-8'))
                  seen.add(newHash.digest())
              # Add suffixes.
              for start in range(len(thisSeq) - 1):
                  seen.add(md5(thisSeq[start + 1:].encode('UTF-8')).digest())
              yield s