error in trajectorylearning.py

[johnwaneboy]

[ERROR] [1646405233.921813, 1401.703000]: bad callback: <bound method TrajectoryLearning.callback_control_command of <ControllerLearning.TrajectoryLearning.TrajectoryLearning object at 0x7fc399691438>>
Traceback (most recent call last):
File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/topics.py", line 750, in _invoke_callback
cb(msg)
File "/home/wane/drone_acrobatics_ws/catkin_dda/src/deep_drone_acrobatics/controller_learning/src/ControllerLearning/TrajectoryLearning.py", line 158, in callback_control_command
self._generate_control_command()
File "/home/wane/drone_acrobatics_ws/catkin_dda/src/deep_drone_acrobatics/controller_learning/src/ControllerLearning/TrajectoryLearning.py", line 180, in _generate_control_command
results = self.learner.inference(inputs)
File "/home/wane/.local/lib/python3.6/site-packages/tensorflow/python/eager/def_function.py", line 402, in call
return self._stateless_fn(*args, **kwds) # pylint: disable=not-callable
TypeError: 'NoneType' object is not callable