New: Adds better feedback on wrong return values.

[matthias-mayr]

Before, a failing "onStart" was difficult to detect. Also if no return value was provided. A wrong 'execute' return value resulted in a failing assertion.

When "onStart" does not succeed, only this feedback was provided by SkiROS:

[BtTicker]          Execution starts.
[VisitorStart]      Root-task_43(State.Running)[]
[Autoparametrize]   Resolving skiros:KpListener:['Robot']
MatchWm             skiros:KpListener:[Robot=cora:Robot-1-cp:ur5e_robot]
[VisitorStart]      KpListener-kp_listener(State.Failure)[Keypoints:[] MaxAge:[0.2] Robot: cora:Robot-1-cp:ur5e_robot ]
[VisitorExecute]    Root-task_43(State.Failure)[]
[BtTicker]          Execution stops.

I would not expect that people actively build a failing "onStart" function in their program flow. If this would be the case, the warning should only be given if it is something else than "False" to help the people who forget the return value.

[frvd]

Nice!

[matthias-mayr]

It looks like I was a bit too quick with the return value of "execute". The line should have been

if type(return_state) is not State:

Also the assert can go now. It would not be reached.