I want to know the answer to the following question:
Which opera director did Frédéric see works of during his stay in Berlin?
All the background I'm provided with is that "On an 1829 return trip to Berlin, he was a guest of Prince Antoni Radziwiłł, governor of the Grand Duchy of Posen—himself an accomplished composer and aspiring cellist.". Is that enough to answer the question?
Answer: no