Add kml layer to map in python notebook

[JackiBergman]

I'm trying to add a kml file to an existing webmap using a python notebook, but I keep getting the error

"Item object without layers or tables is not supported"

Here's my code-

kml_file = gis.content.search(query=my_project, item_type='kml')
project_kml = gis.content.get(kml_file[0].id)
DTE_webmap = WebMap(DTE_map)
DTE_webmap.add_layer(project_kml)
DTE_webmap.update()