def _get_model(model_identifier):
    """
    Helper to look up a model from an "app_label.model_name" string.
    """
    try:
        return apps.get_model(model_identifier)
    except (LookupError, __HOLE__):
        raise base.DeserializationError("Invalid model identifier: '%s'" % model_identifier)
dataset/ETHPy150Open django/django/django/core/serializers/python.py/_get_model