code: public <RO> SingleRuleContext<DPO, TDPO, RO> check(Rule<TDPO, RO> rule) {
          List<Rule<TDPO, RO>> addedRules = new ArrayList<Rule<TDPO, RO>>();
          if (rule != null) {
              addedRules.add(rule);
          }
  
          // Change context
          return new SingleRuleContext<DPO, TDPO, RO>(addedTriggers, addedDataProviders, dataProviderToRuleMapping,
                  addedRuleInputTransformers, addedRules);
      }
docs: Adds the specified rule to the validator under construction.
  
  @param rule Rule to be added.
  @param <RO> Type of rule output.
  
  @return Context allowing further construction of the validator using the DSL.