code: @Override
      public boolean applyCardinality( String inputKey, Object input, WalkedPath walkedPath, Object parentContainer ) {
  
          MatchedElement thisLevel = getMatch( inputKey, walkedPath );
          if ( thisLevel == null ) {
              return false;
          }
          performCardinalityAdjustment( inputKey, input, walkedPath, (Map) parentContainer, thisLevel );
          return true;
      }
docs: If this CardinalitySpec matches the inputkey, then do the work of modifying the data and return true.
  
  @return true if this this spec "handles" the inputkey such that no sibling specs need to see it