Question: Who is the director of the movie "The Magic Christian" in which Peter Sellers was acted?

full_context: Document 1: A Hard Day's Night (film): A Hard Day's Night is a 1964 British musical comedy film directed by Richard Lester and starring the Beatles—John Lennon, Paul McCartney, George Harrison, and Ringo Starr—during the height of Beatlemania. It was written by Alun Owen and originally released by United Artists. The film portrays several days in the lives of the group.
Document 2: The Beatles in film: The Beatles appeared in five motion pictures, most of which were very well received. The exception was the (mostly unscripted) television film "Magical Mystery Tour" which was panned by critics and the public alike. Each of their films had the same name as their associated soundtrack album and a song on that album.
Document 3: Ringo Starr filmography: In addition to the Beatles' films "A Hard Day's Night" (1964), "Help!" (1965), "Magical Mystery Tour" (1967), "Yellow Submarine" (1968) and "Let It Be" (1970), Ringo Starr also acted in films such as "Candy" (1968), "The Magic Christian" (1969, alongside Peter Sellers), "Blindman" (1971), "Son of Dracula" (1974) and "Caveman" (1981).
Document 4: Help! (film): Help! is a 1965 British musical comedy-adventure film directed by Richard Lester, starring the Beatles–John Lennon, Paul McCartney, George Harrison and Ringo Starr—and featuring Leo McKern, Eleanor Bron, Victor Spinetti, John Bluthal, Roy Kinnear and Patrick Cargill. The second film starring The Beatles following Lester's "A Hard Day's Night", "Help!" sees the group come up against an evil cult. The soundtrack was released as an album, also called "Help!".
Document 5: Yellow Submarine (film): Yellow Submarine (also known as The Beatles: Yellow Submarine) is a 1968 British animated musical fantasy comedy film inspired by the music of the Beatles, directed by animation producer George Dunning, and produced by United Artists and King Features Syndicate. Initial press reports stated that the Beatles themselves would provide their own character voices; however, aside from composing and performing the songs, the real Beatles participated only in the closing scene of the film, while their cartoon counterparts were voiced by other actors.
Document 6: The Magic Christian (film): The Magic Christian is a 1969 British satirical black comedy film directed by Joseph McGrath and starring Peter Sellers and Ringo Starr, with appearances by John Cleese, Graham Chapman, Raquel Welch, Spike Milligan, Christopher Lee, Richard Attenborough and Roman Polanski. It was loosely adapted from the 1959 comic novel of the same name by American author Terry Southern, who co-wrote the screenplay adaptation with McGrath.
Document 7: Magic Christian Music: Magic Christian Music is the debut album by the British rock band Badfinger, released in early 1970 on Apple Records. Three tracks from the LP are featured in the film "The Magic Christian", which also gives the album its title. However, "Magic Christian Music" is not an official soundtrack album for the film.
Document 8: Ringo's Rotogravure: Ringo's Rotogravure is the fifth studio album by Ringo Starr, released in 1976. It would turn out to be the last album featuring active involvement from all four former Beatles before John Lennon's death in 1980. Following the end of his contract with EMI, Starr signed on with Polydor Records worldwide (Atlantic Records handling US distribution).
Document 9: The Comedians (1967 film): The Comedians is a 1967 film directed and produced by Peter Glenville, based on the novel of the same name by Graham Greene, who also wrote the screenplay. The stars were Richard Burton, Elizabeth Taylor, Peter Ustinov, and Alec Guinness.
Document 10: Monty Python and the Holy Grail: Monty Python and the Holy Grail is a 1975 British absurdist comedy film concerning the Arthurian legend, written and performed by the Monty Python comedy group (Graham Chapman, John Cleese, Terry Gilliam, Eric Idle, Terry Jones, and Michael Palin), and directed by Gilliam and Jones. It was conceived during the hiatus between the third and fourth series of their BBC television series "Monty Python's Flying Circus".
Document 11: Magical Mystery Tour (film): Magical Mystery Tour is a 52-minute-long British surreal comedy television film starring the Beatles (John Lennon, Paul McCartney, George Harrison and Ringo Starr) which originally aired on BBC1 on Boxing Day, 26 December 1967. Upon its initial showing, the film was poorly received by critics and audiences. The film received an American theatrical release in 1974 by New Line Cinema, and in select theatres worldwide in 2012 by Apple Films.
Document 12: Ringo Starr: Richard Starkey, {'1': ", '2': ", '3': ", '4': "} (born 7 July 1940), known professionally as Ringo Starr, is an English drummer, singer, songwriter and actor who gained worldwide fame as the drummer for the Beatles. He occasionally sang lead vocals, usually for one song on an album, including "With a Little Help from My Friends", "Yellow Submarine", "Good Night", and their cover of "Act Naturally". He also wrote the Beatles' songs "Don't Pass Me By" and "Octopus's Garden", and is credited as a co-writer of others, including "What Goes On" and "Flying".
Document 13: The Magic Christian (novel): The Magic Christian is a 1959 comic novel by American author Terry Southern (1924–1995) about an odd billionaire who spends most of his time playing elaborate practical jokes on people. It is known for bringing Southern to the attention of filmmaker Stanley Kubrick, who had received a copy as a gift from Peter Sellers, and subsequently hired him as co-writer for "Dr. Strangelove" (1964) when Kubrick decided to make that film a black comedy/satire, rather than a straightforward thriller. In 1969, "The Magic Christian" was made into a film starring Peter Sellers and Ringo Starr; the story was much altered and relocated from New York City to London.
Document 14: Graham Chapman: Graham Arthur Chapman (8 January 1941 – 4 October 1989) was an English comedian, writer, actor, author, and one of the six members of the British surreal comedy group Monty Python. He played authority figures such as the Colonel and the lead role in two Python films, "Holy Grail" and "Life of Brian".
Document 15: Monty Python's Life of Brian: Monty Python's Life of Brian, also known as Life of Brian, is a 1979 British religious satire comedy film starring and written by the comedy group Monty Python (Graham Chapman, John Cleese, Terry Gilliam, Eric Idle, Terry Jones and Michael Palin). It was also directed by Jones. The film tells the story of Brian Cohen (played by Chapman), a young Jewish man who is born on the same day as, and next door to, Jesus Christ, and is subsequently mistaken for the Messiah.
ground_truth: Joseph McGrath