code: @Override
      public void setVariables(Map<String, String> variables) {
          injectVariables(variables, element);
  
          /**
           * This is valid:
           * <code>
           *     select(element(ById.class, "element-id"})).index(intVar("element-index"))
           * </code>
           * and it will be resolved to
           */
          if (optionSelector instanceof StringVariable) {
              Variable<String> variable = (StringVariable) optionSelector;
              optionSelector = variable.getConvertedValue(variables);
          } else if (optionSelector instanceof IntegerVariable) {
              Variable<Integer> variable = (IntegerVariable) optionSelector;
              optionSelector = variable.getConvertedValue(variables);
          }
      }
docs: {@inheritDoc}