(Program
  (Function
    (Empty)
    (Empty)
    (Identifier)
    (RequiredParameter
      (Empty)
      (Empty)
      (Empty)
      (Assignment
        (Identifier)
        (Empty)))
    (RequiredParameter
      (Empty)
      (Empty)
      (Empty)
      (Assignment
        (Identifier)
        (Empty)))
    (
      (Yield
        (Empty))
      (Yield
        (Identifier))))
  (Empty))