docs: public static Object getConvertedUISelectManyValue(
              FacesContext facesContext, UISelectMany selectMany,
              Object submittedValue, boolean considerValueType)
              throws ConverterException
      {
          if (submittedValue == null)
          {
              return null;
          }
  
          if (!(submittedValue instanceof String[]))
          {
              throw new ConverterException(
                      "Submitted value of type String[] for component : "
                              + getPathToComponent(selectMany) + "expected");
          }
  
          return _SharedRendererUtils.getConvertedUISelectManyValue(facesContext,
                  selectMany, (String[]) submittedValue, considerValueType);
      }