pymel.util.arguments.mergeCascadingDicts

mergeCascadingDicts(from_dict, to_dict, allowDictToListMerging=False)

recursively update to_dict with values from from_dict. if allowDictToListMerging is True, then if to_dict contains a list, from_dict can contain a dictionary with int keys which can be used to sparsely update the list”.