docs: public boolean hasMandatoryChildNodeDefinitions( Name primaryType,
                                                       Set<Name> mixinTypes ) {
          if (mandatoryChildrenNodeTypes.containsKey(primaryType)) return true;
          for (Name mixinType : mixinTypes) {
              if (mandatoryChildrenNodeTypes.containsKey(mixinType)) return true;
          }
          return false;
      }