If you are using pip package manager, you can use “pip freeze” command to see what packages you have installed (the packages are installed in the “site-packages” folder where you have installed Python) and you may install grpcio1.0.2rc0 by running “pip install grpcio==1.0.2rc0”. If not, let me know what package manager you are using.
I should add that Google Groups is reserved for general product discussions and not for reporting issues. So, I recommend that you report this issue in the Issue Tracker and provide more details on how to reproduce it since Issue Tracker is for reporting Google Cloud Platform-end issues and feature requests.