code: def get_source_langs(lang_pairs: List[str]) -> List[str]:
      """
      Return list of source languages from args.lang_pairs
      lang_pairs: List[str] where each element is a str with comma separated list
      of language pairs
      """
      return [lang_pair.split("-")[0] for lang_pair in lang_pairs]
  
file_path: translate/pytorch_translate/multilingual_utils.py
imports: import argparse
  import os
  from collections import defaultdict
  from typing import Dict, List, Optional, Tuple
  from pytorch_translate.data import dictionary
label_desc: Use image node_id 1 for calling a global function with example usage: get_source_langs(lang_pairs) and returns: unknown