<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def compile_files(raw_dir, raw_files, tag):
 """Compile raw files into a single file for each language. Args: raw_dir: Directory containing downloaded raw files. raw_files: Dict containing filenames of input and target data. {"inputs": list of files containing data in input language "targets": list of files containing corresponding data in target language } tag: String to append to the compiled filename. Returns: Full path of compiled input and target files. """

  tf.logging.info("Compiling files with tag %s." % tag)
  filename = "%s-%s" % (_PREFIX, tag)
  input_compiled_file = os.path.join(raw_dir, filename + ".lang1")
  target_compiled_file = os.path.join(raw_dir, filename + ".lang2")

  with tf.gfile.Open(input_compiled_file, mode="w") as input_writer:
    with tf.gfile.Open(target_compiled_file, mode="w") as target_writer:
      for i in range(len(raw_files["inputs"])):
        input_file = raw_files["inputs"][i]
        target_file = raw_files["targets"][i]

        tf.logging.info("Reading files %s and %s." % (input_file, target_file))
        write_file(input_writer, input_file)
        write_file(target_writer, target_file)
  return input_compiled_file, target_compiled_file