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: test_cluster_shim.go
    path of file: ./repos/cockroach/pkg/testutils/serverutils
    
    the code of the file until where you have to start completion: // Copyright 2016 The Cockroach Authors.
//
// Use of this software is governed by the Business
    
func NewCluster(t TestFataler, numNodes int, args base.TestClusterArgs) TestClusterInterface {
	if clusterFactoryImpl == nil {
		panic("TestClusterFactory not initialized. One needs to be injected " +
			"from the package's TestMain()")
	}
	return clusterFactoryImpl.NewTestCluster(t, numNodes, args)
}