code: def write_last_and_beds(pf, GenePositions, ContigStarts):
      
      qbedfile = pf + "tigs.bed"
      sbedfile = pf + "chr.bed"
      lastfile = "{}tigs.{}chr.last".format(pf, pf)
      qbedfw = open(qbedfile, "w")
      sbedfw = open(sbedfile, "w")
      lastfw = open(lastfile, "w")
  
      GeneContigs = np.searchsorted(ContigStarts, GenePositions) - 1
      for i, (c, gstart) in enumerate(zip(GeneContigs, GenePositions)):
          gene = "gene{:05d}".format(i)
          tig = "tig{:04d}".format(c)
          start = ContigStarts[c]
          cstart = gstart - start
          print("\t".join(str(x) for x in
                                     (tig, cstart, cstart + 1, gene)), file=qbedfw)
          print("\t".join(str(x) for x in
                                     ("chr1", gstart, gstart + 1, gene)), file=sbedfw)
          lastatoms = [gene, gene, 100] + [0] * 8 + [100]
          print("\t".join(str(x) for x in lastatoms), file=lastfw)
  
      qbedfw.close()
      sbedfw.close()
      lastfw.close()
docs: Write LAST file, query and subject BED files.