(Program
  (Module
    (Identifier))
  (Function
    (Empty)
    (Identifier)
    (
      (Call
        (Identifier)
        (BiDirectionalChannel
          (Identifier))
        (Empty))
      (Call
        (Identifier)
        (BiDirectionalChannel
          (Identifier))
        (Minus
          (Identifier)
          (Identifier))
        (Empty))
      (Call
        (Identifier)
        (BiDirectionalChannel
          (Identifier))
        (Integer)
        (Integer)
        (Empty))
      (Call
        (Identifier)
        (Map
          (Identifier)
          (Identifier))
        (Empty)))))