Please answer a question about the following article about Madonna (entertainer):

In 1992, Madonna had a role in A League of Their Own as Mae Mordabito, a baseball player on an all-women's team. She recorded the film's theme song, "This Used to Be My Playground", which became a Hot 100 number one hit. The same year, she founded her own entertainment company, Maverick, consisting of a record company (Maverick Records), a film production company (Maverick Films), and associated music publishing, television broadcasting, book publishing and merchandising divisions. The deal was a joint venture with Time Warner and paid Madonna an advance of $60 million. It gave her 20% royalties from the music proceedings, one of the highest rates in the industry, equaled at that time only by Michael Jackson's royalty rate established a year earlier with Sony. The first release from the venture was Madonna's book, titled Sex. It consisted of sexually provocative and explicit images, photographed by Steven Meisel. The book received strong negative reaction from the media and the general public, but sold 1.5 million copies at $50 each in a matter of days. At the same time she released her fifth studio album, Erotica, which debuted at number two on the Billboard 200. Its title track peaked at number three on the Billboard Hot 100. Erotica also produced five singles: "Deeper and Deeper", "Bad Girl", "Fever", "Rain" and "Bye Bye Baby". Madonna had provocative imagery featured in the erotic thriller, Body of Evidence, a film which contained scenes of sadomasochism and bondage. It was poorly received by critics. She also starred in the film Dangerous Game, which was released straight to video in North America. The New York Times described the film as "angry and painful, and the pain feels real."

What is the film's theme song?
This Used to Be My Playground