human
I wrote the below code

    app_id = kwargs.pop('app_id', None)
    if kwargs:
        raise TypeError(('Invalid    arguments:    %s' % ',    '.join(kwargs)))
    request = search_service_pb.ListIndexesRequest()
    params = request.mutable_params()
    if (namespace is None):
        namespace = namespace_manager.get_namespace()
    if (namespace is None):
        namespace = u''
    namespace_manager.validate_namespace(namespace, exception=ValueError)
    params.set_namespace(namespace)
    if (offset is not None):
        params.set_offset(_CheckInteger(offset, 'offset', zero_ok=True, upper_bound=MAXIMUM_GET_INDEXES_OFFSET))
    params.set_limit(_CheckInteger(limit, 'limit', zero_ok=False, upper_bound=MAXIMUM_INDEXES_RETURNED_PER_GET_REQUEST))
    if (start_index_name is not None):
        params.set_start_index_name(_ValidateString(start_index_name, 'start_index_name', MAXIMUM_INDEX_NAME_LENGTH, empty_ok=False))
    if (include_start_index is not None):
        params.set_include_start_index(bool(include_start_index))
    if (index_name_prefix is not None):
        params.set_index_name_prefix(_ValidateString(index_name_prefix, 'index_name_prefix', MAXIMUM_INDEX_NAME_LENGTH, empty_ok=False))
    params.set_fetch_schema(fetch_schema)
    response = search_service_pb.ListIndexesResponse()
    if app_id:
        request.set_app_id(app_id)
    def hook():
        _CheckStatus(response.status())
        return _ListIndexesResponsePbToGetResponse(response, fetch_schema)
    return _RpcOperationFuture('ListIndexes', request, response, deadline, hook)

What's a good function header?
 Can you provide a Python program to fix is not None):?
assistant
#Here is Python program to fix is not None):
.

@datastore_rpc._positional(7)
def get_indexes_async(namespace='', offset=None, limit=20, start_index_name=None, include_start_index=True, index_name_prefix=None, fetch_schema=False, deadline=None, **kwargs):