code: def decomment(bed_file, out_file):
      
      if file_exists(out_file):
          return out_file
  
      with utils.open_gzipsafe(bed_file) as in_handle, open(out_file, "w") as out_handle:
          for line in in_handle:
              if line.startswith("#") or line.startswith("browser") or line.startswith("track"):
                  continue
              else:
                  out_handle.write(line)
      return out_file
docs: clean a BED file