How to make an existing workbook scoped asset tree Global?

[JDLom]

Hi,

After a lot of testing and validation I want to move my existing asset tree from a local workbook to a global one 

however this does not work: 

# Push the tree globally
existing_tree.push(workbook=None)

TypeError: Tree.push() got an unexpected keyword argument 'workbook'

Is it not possible to make a tree global when it's already scoped to a workbook? and what would be the ideal way of adjusting a tree, testing it in a local workbook and push changes global again ?