def generate(self, generate_method: BigGenerateMethod, parameter: Union[str, int]):
        """
        In order to embed it to the show_base loop, we implement BIG in a more complex way
        """
        if generate_method == BigGenerateMethod.BLOCK_NUM:
            assert isinstance(parameter, int), "When generating map by assigning block num, the parameter should be int"
            self.block_num = parameter + 1
        elif generate_method == BigGenerateMethod.BLOCK_SEQUENCE:
            assert isinstance(parameter, str), "When generating map from block sequence, the parameter should be a str"
            self.block_num = len(parameter) + 1
            self._block_sequence = FirstPGBlock.ID + parameter
        while True:
            if self.big_helper_func():
                break
        return self._global_network

        In order to embed it to the show_base loop, we implement BIG in a more complex way
        
metadrive/component/map/city_map.py