Use `...` for unimplemented property in arg parsing
Use `...` for unimplemented property in arg parsing

Summary: No need for exceptions, `....` will suffice as ABC machinery does the rest

Reviewed By: c-ryan747

Differential Revision: D25883829

fbshipit-source-id: cabe21a0b7e3e76c06555a05ab05bede75a52e15

facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl,facebook/FBSimulatorControl