Add node values from dataframe

[abogadoRobot]

Firstly, thank you for this amazing package!

I am struggling to add a similar values as "SizeOfNode" on every parent node, but with strings. I am able to add attributes in every children modifiying your collapsibleTree function, nonetheless without any luck with nodes.

Example of generated json with SizeofNode value:
{
"name" : "Test Name",
"SizeofNode": 24.11, # below every parent I need to add a string
"children":[{
...
}]

}
Thanks again for your time and amazing work.