The `codes.Unimplemented` is only returned when the RPCs are not built. When the wallet is in an unexpected state, `codes.Unknown` is returned instead, so we need to catch it properly to make sure we return the right error msg.
The `codes.Unimplemented` is only returned when the RPCs are not built. When the wallet is in an unexpected state, `codes.Unknown` is returned instead, so we need to catch it properly to make sure we return the right error msg.