code: @NonNull
      public Transition removeTarget(@Nullable Class target) {
          if (target != null && mTargetTypes != null) {
              mTargetTypes.remove(target);
          }
          return this;
      }
docs: Removes the given target from the list of targets that this Transition
  is interested in animating.
  
  @param target The type of the target view, must be non-null.
  @return Transition The Transition from which the target is removed.
  Returning the same object makes it easier to chain calls during
  construction, such as
  <code>transitionSet.addTransitions(new Fade()).removeTarget(someType);</code>