code: def junction2bed(junction_file):
      
      base, _ = os.path.splitext(junction_file)
      out_file = base + "-minimized.bed"
      if file_exists(out_file):
          return out_file
      if not file_exists(junction_file):
          return None
      with file_transaction(out_file) as tx_out_file:
          with open(junction_file) as in_handle:
              with open(tx_out_file, "w") as out_handle:
                   for line in in_handle:
                      tokens = line.split()
                      chrom, sj1, sj2 = tokens[0:3]
                      if int(sj1) > int(sj2):
                          tmp = sj1
                          sj1 = sj2
                          sj2 = tmp
                      out_handle.write("\t".join([chrom, sj1, sj1]) + "\n")
                      out_handle.write("\t".join([chrom, sj2, sj2]) + "\n")
          minimize = bed.minimize(tx_out_file)
          minimize.saveas(tx_out_file)
      return out_file
docs: reformat the STAR junction file to BED3 format, one end of the splice junction per line