How to delete a property from Y.Doc

1

I want to do something like

const doc = new Y.Doc()

doc.getMap('a')
doc.getMap('b')

doc.delete('a') // <--
2

Nest it in a top-level map:

// set
const doc = new Y.Doc()
const rootMap = doc.getMap('root')
rootMap.set('a', new Y.Map())
rootMap.get('a')

// del
doc.getMap('root').delete('a')
3

This is not possible since our design is not like that