docs: @Override
      public boolean applyCardinality( String inputKey, Object input, WalkedPath walkedPath, Object parentContainer ) {
          MatchedElement thisLevel = pathElement.match( inputKey, walkedPath );
          if ( thisLevel == null ) {
              return false;
          }
  
          walkedPath.add( input, thisLevel );
  
          // The specialChild can change the data object that I point to.
          // Aka, my key had a value that was a List, and that gets changed so that my key points to a ONE value
          if (specialChild != null) {
              input = specialChild.applyToParentContainer( inputKey, input, walkedPath, parentContainer );
          }
  
          // Handle the rest of the children
          process( input, walkedPath );
  
          walkedPath.removeLast();
          return true;
      }