def _is_pair(obj):
  return isinstance(obj, tuple) and len(obj) == 2
Entity must be ISO 639-1 code.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/memcache/__init__.py/_is_pair--crossover with--dataset/ETHPy150Open heiskr/sagefy/server/modules/validations.py/is_language