code: @Nullable
      public static <P extends Presenter> ReflectionPresenterFactory<P> fromViewClass(Class<?> viewClass) {
          RequiresPresenter annotation = viewClass.getAnnotation(RequiresPresenter.class);
          //noinspection unchecked
          Class<P> presenterClass = annotation == null ? null : (Class<P>)annotation.value();
          return presenterClass == null ? null : new ReflectionPresenterFactory<>(presenterClass);
      }
docs: This method returns a {@link ReflectionPresenterFactory} instance if a given view class has
  a {@link RequiresPresenter} annotation, or null otherwise.
  
  @param viewClass a class of the view
  @param <P>       a type of the presenter
  @return a {@link ReflectionPresenterFactory} instance that is supposed to create a presenter from {@link RequiresPresenter} annotation.