To regenerate go server code:
protoc \
--go_out=go_calculator \
--go_opt=paths=source_relative \
--go-grpc_out=go_calculator \
--go-grpc_opt=paths=source_relative \
calculator.proto
To regenerate python client code:
python3 -m grpc_tools.protoc \
--proto_path=. \
--python_out=. \
--grpc_python_out=. \
calculator.proto