Use the right type

Author: fayazkhan

sqlalchemy_mptt/tests/test_events.py

@@ -192,7 +192,7 @@ def test_documented_initial_insert(self):
 
         tree_manager.register_events(remove=True)  # Disable MPTT events
 
-        _tree_id = 'tree1'
+        _tree_id = 1
 
         for node_id, parent_id in [(1, None), (2, 1), (3, 1), (4, 2)]:
             item = Tree(