code: def to_pb(self):
          
  
          return policy_pb2.Policy(
              etag=self.etag,
              version=self.version or 0,
              bindings=[
                  policy_pb2.Binding(role=role, members=sorted(self[role]))
                  for role in self
              ],
          )
docs: Render a protobuf message.
  
          Returns:
              google.iam.policy_pb2.Policy: a message to be passed to the
              ``set_iam_policy`` gRPC API.