def _ApplyStorageInfoFunction(storage_type, storage_key, *args):
  fn = _STORAGE_TYPE_INFO_FN[storage_type]
  if fn is not None:
    return fn(storage_key, *args)
  else:
    raise NotImplementedError
Looks up and applies the correct function to calculate free and total
dataset/ETHPy150Open ganeti/ganeti/lib/backend.py/_ApplyStorageInfoFunction