code: func NewClient(opts *ClientOptions) *Client {
  	cli := opts.Client
  	if cli == nil {
  		cli = http.DefaultClient
  	}
  	client := &Client{
  		caller: &defaultCaller{
  			client: cli,
  			headers: map[string]string{
  				"GDPR-Version": ApiVersion,
  				"Content-Type": "Application/JSON",
  			},
  		},
  		endpoint: opts.Endpoint,
  		verifier: opts.Verifier,
  	}
  	return client
  }
docs: // NewClient returns a new OpenGDPR client.