0(1) element: null
1(2) element: PyTypeParameter
2(3) WRITE ACCESS: T
3(4) READ ACCESS: str
4(5) element: PyTypeParameter
5(6) WRITE ACCESS: U
6(7) READ ACCESS: int
7(8) element: PySubscriptionExpression
8(9) READ ACCESS: Union
9(10) READ ACCESS: T
10(11) READ ACCESS: U
11() element: null