I want to know the answer to the following question:
What anniversary was the July Revolution that Sand and Chopin were present at a dress rehearsal for?
All the background I'm provided with is that "At the funeral of the tenor Adolphe Nourrit in Paris in 1839, Chopin made a rare appearance at the organ, playing a transcription of Franz Schubert's lied Die Gestirne.". Is that enough to answer the question?
Answer: no