code: public final <T extends GraphObject> T getGraphObjectAs(Class<T> graphObjectClass) {
          if (graphObject == null) {
              return null;
          }
          if (graphObjectClass == null) {
              throw new NullPointerException("Must pass in a valid interface that extends GraphObject");
          }
          return graphObject.cast(graphObjectClass);
      }
docs: The single graph object returned for this request, if any, cast into a particular type of GraphObject.
  
  @param graphObjectClass the GraphObject-derived interface to cast the graph object into
  @return the graph object returned, or null if none was returned (or if the result was a list)
  @throws FacebookException If the passed in Class is not a valid GraphObject interface