0(1) element: null
1(2) element: PyWhileStatement
2(3,11) READ ACCESS: x
3(4) element: PyStatementList. Condition: x:true
4(5) element: PyMatchStatement
5(6) READ ACCESS: x
6(7,9) refutable pattern: 42
7(8) matched pattern: 42
8(11) element: PyBreakStatement
9(10) element: PyExpressionStatement
10(1) READ ACCESS: y
11(12) element: PyExpressionStatement
12(13) READ ACCESS: z
13() element: null