code: def _uniq_rec(fastafile, seq=False):
      
      seen = set()
      for rec in SeqIO.parse(fastafile, "fasta"):
          name = str(rec.seq) if seq else rec.id
          if name in seen:
              logging.debug("ignore {0}".format(rec.id))
              continue
          seen.add(name)
          yield rec
docs: Returns unique records