code: func (h *Client) DocumentPath(documentPath string) *Client {
  	h.documentPath = documentPath
  	h.documentPathSet = true
  	return h
  }
docs: // The path portion of the page URL. Should begin with '/'.
  // For 'pageview' hits, either &dl or both &dh and &dp have
  // to be specified for the hit to be valid.