0(1) element: null
1(2) element: PyMatchStatement
2(3,11) refutable pattern: [1, foo.bar]
3(4,11) refutable pattern: 1
4(5) matched pattern: 1
5(6,11) refutable pattern: foo.bar
6(7) READ ACCESS: foo
7(8) matched pattern: foo.bar
8(9) matched pattern: [1, foo.bar]
9(10) element: PyExpressionStatement
10(11) READ ACCESS: x
11(12) element: PyExpressionStatement
12(13) READ ACCESS: y
13() element: null