code: def lastz_2bit(t):
      
      bfasta_fn, afasta_fn, outfile, lastz_bin, extra, mask, format = t
  
      ref_tags = [Darkspace]
      qry_tags = [Darkspace]
      ref_tags, qry_tags = add_mask(ref_tags, qry_tags, mask=mask)
  
      lastz_cmd = Lastz_template.format(lastz_bin, bfasta_fn, ref_tags, \
                                                   afasta_fn, qry_tags)
      if extra:
          lastz_cmd += " " + extra.strip()
  
      lastz_cmd += " --format={0}".format(format)
      proc = Popen(lastz_cmd)
      out_fh = open(outfile, "w")
  
      logging.debug("job <%d> started: %s" % (proc.pid, lastz_cmd))
      for row in proc.stdout:
          out_fh.write(row)
          out_fh.flush()
      logging.debug("job <%d> finished" % proc.pid)
docs: Used for formats other than BLAST, i.e. lav, maf, etc. which requires the
      database file to contain a single FASTA record.