Housekeeping: Make return value explicit, catch missing pydot, etc.
Housekeeping: Make return value explicit, catch missing pydot, etc.

necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,necozay/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control,tulip-control/tulip-control