You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cluster_resolver.go
    path of file: ./repos/pixie/src/cloud/api/controllers
    
    the code of the file until where you have to start completion: /*
 * Copyright 2018- The Pixie Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agree
    
func (q *QueryResolver) Cluster(ctx context.Context, args *clusterArgs) (*ClusterInfoResolver, error) {
	grpcAPI := q.Env.VizierClusterInfo
	res, err := grpcAPI.GetClusterInfo(ctx, &cloudpb.GetClusterInfoRequest{
		ID: utils.ProtoFromUUIDStrOrNil(string(args.ID)),
	})
	if err != nil {
		return nil, rpcErrorHelper(err)
	}
	if len(res.Clusters) == 0 {
		return nil, errors.New("org has no matching clusters")
	}
	if len(res.Clusters) != 1 {
		return nil, errors.New("got multiple matching clusters for ID")
	}
	return clusterInfoToResolver(res.Clusters[0])
}