(Program
  (Comprehension
    (Identifier)
    (
      (
        (Identifier)
        (Identifier))
      (Call
        (Identifier)
        (Empty))
      (
        (Identifier)
        (Identifier))
      (Call
        (Identifier)
        (Empty))))
  (Comprehension
    (Plus
      (Identifier)
      (Integer))
    (
      (Identifier)
      (Identifier))))