docs: def split_sequence_file_on_sample_ids_to_files(seqs,
                                                 outdir):
      """Split FASTA file on sample IDs.
  
      Parameters
      ----------
      seqs: file handler
          file handler to demultiplexed FASTA file
      outdir: string
          dirpath to output split FASTA files
      """
      logger = logging.getLogger(__name__)
      logger.info('split_sequence_file_on_sample_ids_to_files'
                  ' for file %s into dir %s' % (seqs, outdir))
  
      outputs = {}
  
      for bits in sequence_generator(seqs):
          sample = sample_id_from_read_id(bits[0])
  
          if sample not in outputs:
              outputs[sample] = open(join(outdir, sample + '.fasta'), 'w')
          outputs[sample].write(">%s\n%s\n" % (bits[0], bits[1]))
      for sample in outputs:
          outputs[sample].close()
      logger.info('split to %d files' % len(outputs))