interface simple-lists {
  simple-list1: func(l: list<u32>)
  simple-list2: func() -> list<u32>
  simple-list3: func(a: list<u32>, b: list<u32>) -> tuple<list<u32>, list<u32>>
  simple-list4: func(l: list<list<u32>>) -> list<list<u32>>
}

default world my-world {
  import imports: self.simple-lists
  export exports: self.simple-lists
}