Error while running

I am getting error in line 32 of optimizer.py . Line 32 is  
        self.__nn_pred = neural_net.e.network(self.__domain)
 and the error is  (TypeError: 'Regressor' object is not callable
Exception TypeError: TypeError("'NoneType' object is not callable")

There is no function by name 'network' in neural_net.py, so when we call neural_net.e.network, it's throwing up an error. 