Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

william frederick "buffalo bill" cody (february 26, 1846 – january 10, 1917) was an american soldier, bison hunter and showman.
buffalo bill

the british rail class 931 was reserved for former southern region electrical multiple units converted for departmental use.
british rail class 931

the iraq national under-23 football team are a team who play association football for iraq at the under-23 level.

iraq national under-23 football team