def check_the_end_flag(self, state_arr):
        '''
        Check the end flag.
        
        If this return value is `True`, the learning is end.

        As a rule, the learning can not be stopped.
        This method should be overrided for concreate usecases.

        Args:
            state_arr:    `np.ndarray` of state in `self.t`.

        Returns:
            bool
        '''
        if self.__check_goal_flag(state_arr) is True or self.__check_crash_flag(state_arr):
            return True
        else:
            return False
Check the end flag.
        
        If this return value is `True`, the learning is end.

        As a rule, the learning can not be stopped.
        This method should be overrided for concreate usecases.

        Args:
            state_arr:    `np.ndarray` of state in `self.t`.

        Returns:
            bool