code: protected final void addSharedElement(@NonNull View sharedElement, @NonNull String toName) {
          String transitionName = sharedElement.getTransitionName();
          if (transitionName == null) {
              throw new IllegalArgumentException("Unique transitionNames are required for all sharedElements");
          }
          sharedElementNames.put(transitionName, toName);
      }
docs: Used to register an element that will take part in the shared element transition. Maps the name used in the
  "from" view to the name used in the "to" view if they are not the same.
  
  @param sharedElement The view from the "from" view that will take part in the shared element transition
  @param toName The transition name used in the "to" view