human
I wrote the below code

    def _ResultHook(rpc):
        mapped_errors = [modules_service_pb.ModulesServiceError.INVALID_VERSION]
        _CheckAsyncResult(rpc, mapped_errors, {})
        return rpc.response.instances()
    request = modules_service_pb.GetNumInstancesRequest()
    if module:
        request.set_module(module)
    if version:
        request.set_version(version)
    response = modules_service_pb.GetNumInstancesResponse()
    return _MakeAsyncCall('GetNumInstances', request, response, _ResultHook).get_result()

What's a good function header?
 ... Here's a good function header?
assistant
#Here's a good function header.

def get_num_instances(module=None, version=None):