Allen is Harry's older brother. Yesterday, Allen asked Harry, an experienced plumber, to fix a leaky pipe below the sink of Allen's main floor washroom. Knowing that Allen had just lost his job and wanting to help him out, Harry did the work, which took him almost half a day to complete. The next day, Harry and Allen had an argument, and in anger Harry told Allen he expected to be paid for his work. Is there an enforceable contract here? Why or why not?