code: func DefaultClient() *Client {
  	client, err := NewClient(os.Getenv(APIKeyEnvVar))
  	if err != nil {
  		panic(err)
  	}
  	return client
  }
docs: // DefaultClient instantiates a new Fastly API client. This function requires
  // the environment variable `FASTLY_API_KEY` is set and contains a valid API key
  // to authenticate with Fastly.