build_model.py

def _build_compile_model(self):
        model = Sequential()
        model.add(Conv2D(32, 8, strides=(4, 4), padding="valid",activation="relu", 
                              input_shape = self._image_shape))
        model.add(Conv2D(64, 4, strides=(2, 2), padding="valid", activation="relu",
                              input_shape = self._image_shape))
        model.add(Conv2D(64, 3, strides=(1, 1), padding="valid",activation="relu",
                              input_shape = self._image_shape))
        model.add(Flatten())
        model.add(Dense(512, activation="relu"))
        model.add(Dense(self._action_size))
        huber = Huber()
        model.compile(loss = huber,
                           optimizer=self._optimizer,
                           metrics=["accuracy"])
        return model