Question: The operas that Helen Donaldson was best known for appearing in were created by a team who collaborated on how many comic operas?
Sentence (from "William Charles John Pitcher"): William John Charles Pitcher (21 March 1858 – 2 March 1925), known as Wilhelm or C. Wilhelm, was an English artist, costume and scenery designer, best known for his designs for ballets, pantomimes, comic operas, and Edwardian musical comedies.
Relevant evidence: No