lib/ui: fix human_list for lists with one item

passbook/lib/utils/ui.py

@@ -1,8 +1,11 @@
 """passbook UI utils"""
+from typing import Any, List
 
 
-def human_list(_list) -> str:
+def human_list(_list: List[Any]) -> str:
     """Convert a list of items into 'a, b or c'"""
     last_item = _list.pop()
+    if len(_list) < 1:
+        return last_item
     result = ", ".join(_list)
     return "%s or %s" % (result, last_item)