Question: Irvin Willat and Rowland V. Lee, have which mutual occupation?

Context paragraphs:
Doomsday (1928 film): Doomsday is a 1928 American romance drama silent film directed by Rowland V. Lee and starring Florence Vidor and Gary Cooper.  Written by Julian Johnson, Donald W. Lee, and Doris Anderson, based on the 1927 novel "Doomsday" by Warwick Deeping, the film is about a woman who marries a wealthy landowner to escape her life of poverty, leaving behind the handsome farmer she truly loves.  Produced by Jesse L. Lasky, Rowland V. Lee, Hector Turnbull, and Adolph Zukor for Paramount Pictures, "Doomsday" was released on February 18, 1928 in the United States.

The Isle of Lost Ships (1929 film): The Isle of Lost Ships is a 1929 talking film released in an alternative silent version with a Vitaphone track of effects and music.  It was produced by Richard A. Rowland and distributed by Warner Bros..  Irvin Willat was the director with Jason Robards, Sr. and Virginia Valli in the leads.  It is based on the 1909 novel "The Isle of Dead Ships" by Crittenden Marriott, and is also a remake of Maurice Tourneur's now lost 1923 classic of the same name.  This film is preserved at the Library of Congress.

Rustling a Bride: Rustling A Bride is a lost 1919 silent film comedy-western directed by Irvin Willat and starring Lila Lee.

The Grim Game: The Grim Game is a 1919 American silent drama film directed by Irvin Willat and starring Harry Houdini and Ann Forrest.  The basic plotline serves as a showcase for Houdini's talent as an escapologist, stunt performer and aviator.

The False Faces: The False Faces is a 1919 American silent drama film directed by Irvin Willat from the novel by Louis Joseph Vance and starring Henry B. Walthall as Michael Lanyard, the "Lone Wolf," and Lon Chaney as the villain.  A print of the film survives at George Eastman House.  Lon Chaney's energetic performance remains an early example of his celebrated work.

Irvin Willat: Irvin Willat (November 18, 1890 – April 17, 1976) was an American film director of the silent film era.  He directed 39 films between 1917 and 1937.  Early in his career Willat worked as a cinematographer on several films.

Rowland V. Lee: Rowland Vance Lee (September 6, 1891 in Findlay, Ohio – December 21, 1975 in Palm Desert, California) was an American film director, writer and producer.  In 1929, he directed "The Wolf of Wall Street" featuring George Bancroft.

The Story Without a Name: The Story Without a Name is a 1924 silent film melodrama directed by Irvin Willat and based on a novel by Arthur Stringer.  It was produced by Famous Players-Lasky and distributed by Paramount Pictures.  The film stars Agnes Ayres.  Also known as "Without Warning".  This film is lost.

A Daughter of the Wolf: A Daughter of the Wolf is a 1919 American silent drama film directed by Irvin Willat and written by Marion Fairfax and Hugh Pendexter.  The film stars Lila Lee, Elliott Dexter, Clarence Geldart, Raymond Hatton, Richard Wayne, and Minnie Devereaux.  The film was released on June 22, 1919, by Paramount Pictures.

The Siren Call: The Siren Call is a 1922 American drama silent film directed by Irvin Willat and written by Philip D. Hurn, Victor Irvin and J.E. Nash.  The film stars Dorothy Dalton, David Powell, Mitchell Lewis, Ed Brady, Will Walling, Leigh Wyant and Lucien Littlefield.  The film was released on September 17, 1922, by Paramount Pictures.

Supporting paragraphs: Irvin Willat Rowland V. Lee
Answer: film director