code: @Override
      public void onAttach(Activity activity) {
          super.onAttach(activity);
  
          // expand the activity graph with the fragment-specific module(s)
          ObjectGraph appGraph = ((Injector) activity).getObjectGraph();
          List<Object> fragmentModules = getModules();
          mObjectGraph = appGraph.plus(fragmentModules.toArray());
  
          // make sure it's the first time through; we don't want to re-inject a retained fragment that is going
          // through a detach/attach sequence.
          if (mFirstAttach) {
              inject(this);
              mFirstAttach = false;
          }
      }
docs: Creates an object graph for this Fragment by extending the hosting Activity's object graph with the modules
  returned by {@link #getModules()}.
  <p/>
  Injects this Fragment using the created graph.