code: public MultipleRuleContext<DPO, RI, RO> check(Collection<Rule<RI, RO>> rules) {
          if (rules != null) {
              addedRules.addAll(rules);
          }
  
          // Stay in the same context and re-use the same instance because no type has changed
          return this;
      }
docs: Adds the specified rules to the validator under construction.
  
  @param rules Rules to be added.
  
  @return Context allowing further construction of the validator using the DSL.