Kotlin: AttributeError: 'If' object has no attribute 'body_vars'
In `core_transformers`, `add_variable_context` is run first, adding `body_vars`, including to all `ast.If`.

`pykt.visit_If` expects `body_vars` is set.

Somewhere in the middle, `if`'s are added without `body_vars`.

The sample code is using a `with`, so I presume `WithToBlockTransformer` is to blame.

If I add `body_vars` and `orelse_vars` to `create_ast_node` *and* `create_ast_block`, I get past this, but then I hit another problem.

This is likely 'new' since v0.2.1, but also this isnt syntax which is known to work in Kotlin, so one error is as good as another.