def swap(a: int, b: int) -> tuple[int, int]:
return (b, a)
def first(p: tuple[int, int]) -> int:
return p[0]
def labelled(n: int, s: str) -> tuple[int, str]:
# per-element types preserved: (i64, String)
return (n, s)
def sum_pair(p: tuple[int, int]) -> int:
a, b = p
return a + b