Premise: Robert L. Hass (born March 1, 1941) is an American poet. He served as Poet Laureate of the United States from 1995 to 1997. He won the 2007 National Book Award and shared the 2008 Pulitzer Prize for the collection "Time and Materials: Poems 1997-2005." In 2014 he was awarded the Wallace Stevens Award from the Academy of American Poets.
Hypothesis: Robert Hass only writes poems.