code: @Override
      public boolean containsKey(final Object arg0)
      {
          eagerlyLoadDataCollection();
          final Map dataMap = (Map) dataCollection;
  
          boolean result = false;
  
          if (dataMap != null && !(dataMap instanceof ProxyMap) && !dataMap.isEmpty())
          {
              result = dataMap.containsKey(arg0);
          }
          return result;
      }
docs: ///////////////////////Methods from Map interface ////////////////