Oh I remember that error now. Instead of going thru the list, it wants the list itself, but as an ICollection which is not the same as Python’s lists, if I remember correctly. Try following this thread and see if it works: How to create an icollection to work with revit api
Try adding the following references to the top:
clr.AddReference(“System”)
from System.Collections.Generic import List
Then put in:
ws = List[WorksetId](UnwrapElement(Wss))
and use ws in WorksharingUtils.CheckoutWorksets(doc,ws)
Might need to mess with the unwrapping or looping if that doesn’t work right away.