=str #15152 ast transformations

* for feedback
* only supports Flow map operation
hm, note this ticket #16392
That is about renaming vertex `name` to `key` with the purpose of equality. The name in the attributes is more for descriptive purposes.

As I mentioned in that ticket I'm not sure we need the vertex key at all, so that might solve this also?

For now, can't you just implement `newInstance` as `new RouteVertex(attributes.copy(name = None))`?