I am trying to add a feature layer to a Web Map, and when running the ".add_layer()" method I am getting an error. The error is an AttributeError: 'NoneType' object has no attribute 'append'. Eventually, I would like to be able to run a loop and add the layer to a selection of web maps.
The two photos below show the Jupyter notebook of the steps I took. On a couple occasions, I ran the ".update()" method after the error with the .add_layer and the feature layer was still applied to the map, but this didn't always work.
Any help would be greatly appreciated!