Accept that some python version after 3.9 raises a KeyError instead of TypeError in test case

Author: Code0x58

test_jsonstore.py

@@ -216,7 +216,8 @@ def test_del(self):
             del self.store["list", 1]
 
         self.store.dict = {}
-        with self.assertRaises(TypeError):
+        # somewhere after python 3.9 this went from a TypeError to a KeyError
+        with self.assertRaises((TypeError, KeyError)):
             del self.store["dict", slice("a")]
 
     def test_context_and_deserialisation(self):