new_contents: from argparse import ArgumentParser
  from Bio.Seq import Seq
  from itertools import product
  
  def rc_prepper(barcode):
      return str(Seq(barcode.strip()).reverse_complement())
  
  def normal_prepper(barcode):
      return barcode.strip()
  
  def read_barcode(fn, prepper=normal_prepper):
      with open(fn) as fh:
          return set(prepper(barcode) for barcode in fh)
  
  if __name__ == "__main__":
      description = ("Takes in a set of barcodes and prints out their reverse "
                     "complement. If paired barcodes are given, it prints all "
                     "combinations of BC1+BC2.")
      parser = ArgumentParser()
      parser.add_argument("--rc", action='store_true', default=False,
                          help="Take reverse complement of barcodes.")
      parser.add_argument("--bc1", help="Barcode 1", required=True)
      parser.add_argument("--bc2", help="Barcode 2", default=None, required=True)
  
      args = parser.parse_args()
  
      prepper = rc_prepper if args.rc else normal_prepper
  
      bc1_set = read_barcode(args.bc1, prepper)
      bc2_set = read_barcode(args.bc2, prepper) if args.bc2 else None
  
      if bc2_set:
          for bc1, bc2 in product(bc1_set, bc2_set):
              print bc1 + bc2
      else:
          for bc1 in bc1_set:
              print bc1
  
subject: Add script to prep the klein lab's barcodes.