Conversation so far:
What did Yip Harburg do in Hollywood?
Harburg and Gorney were offered a contract with Paramount: in Hollywood, Harburg worked with composers and later wrote the lyrics for The Wizard of Oz's Over the Rainbow.“

Question: What year did he write for Wizard of Oz?
Self-contained rewrite: What year did Yip Harburg write for Wizard of Oz?