def _ReadBarcodeFromTextFile(barcode_file_name):
  """Reads the decoded barcode for a .txt file.

  Args:
    barcode_file_name(string): The name of the .txt file.
  Return:
    (string): The decoded barcode.
  """
  barcode_file = open(barcode_file_name, 'r')
  barcode = barcode_file.read()
  barcode_file.close()
  return barcode