code: @NonNull
      private Activity getActivity() {
          Activity result = null;
          if (activity != null) {
              result = activity;
          } else if (fragment != null) {
              result = fragment.getActivity();
          } else if (fragmentSupport != null) {
              result = fragmentSupport.getActivity();
          }
          if (result == null) {
              throw new NullPointerException("No activity or fragment instance");
          }
          return result;
      }
docs: /* Helper methods