Ah, very good point!  I didn't think that webidl bindings supported returning array values, and that attribute getters for arrays were the only case.  I was wrong.  I was confused by the fact that the getter for `render_function` was called with the array type's `.name` property; but of course this is without the `[]`.  Instead for array (or rather, sequence) attribute getters I should call `render_function` with the sequence's `.inner.type` and remove this case.  