0(1) element: null
1(2) element: PyAssignmentStatement
2(3) element: PySetCompExpression
3(4,8) element: PyParenthesizedExpression
4(5) element: PyTargetExpression: x
5(6) WRITE ACCESS: x
6(7) element: PyReferenceExpression: x
7(4,8) READ ACCESS: x
8() element: null