Traceback (most recent call last):


 "/home/ubuntu/venvs/robot_env/lib/python3.5/site-packages/ray/tune/trial_runner.py", line 515, in _process_trial

result = self.trial_executor.fetch_result(trial)


 "/home/ubuntu/venvs/robot_env/lib/python3.5/site-packages/ray/tune/ray_trial_executor.py", line 351, in fetch_result

result = ray.get(trial_future[0])


 "/home/ubuntu/venvs/robot_env/lib/python3.5/site-packages/ray/worker.py", line 2121, in get

raise value.as_instanceof_cause()


 "/home/ubuntu/venvs/robot_env/lib/python3.5/site-packages/ray/exceptions.py", line 62, in as_instanceof_cause

class cls(RayTaskError, self.cause_cls):
TypeError: Cannot create a consistent method resolution

Traceback (most recent call last):


 "<stdin>", line 1, in <module>
TypeError: callback() missing 2 required positional arguments: 'a' and 'b'
