@abc.abstractmethod
def get_sub_model(self, sub_model_type):
    "Returns the underlying keras model for the given sub_model_type.\n\n    This function is useful when we only want to get a subset of weights to\n    be restored from a checkpoint.\n\n    Args:\n      sub_model_type: string, the type of sub model. Currently, CenterNet\n        feature extractors support 'detection' and 'classification'.\n    "
    pass
Returns the underlying keras model for the given sub_model_type.

This function is useful when we only want to get a subset of weights to
be restored from a checkpoint.

Args:
  sub_model_type: string, the type of sub model. Currently, CenterNet
    feature extractors support 'detection' and 'classification'.
@abc.abstractmethod
def get_sub_model(self, sub_model_type):
    "Returns the underlying keras model for the given sub_model_type.\n\n    This function is useful when we only want to get a subset of weights to\n    be restored from a checkpoint.\n\n    Args:\n      sub_model_type: string, the type of sub model. Currently, CenterNet\n        feature extractors support 'detection' and 'classification'.\n    "
    pass