Convert Icollection back to list

I found many help with converting a list of element ID to an Icollection for use in python here
( How to create an icollection to work with revit api - Developers - Dynamo (,

however Im stuck with the reverse method. The method i’m trying to use GetSourceElementIds Method spits out an Icollection and I need to get the source element or at least a list of elementIDs any idea how i could do that?

GetSourceElementIds Method (