chore(tests): simplify test

Author: zollqir

tests/python/test_dict_methods.py

@@ -569,6 +569,5 @@ def test_next_operator_non_iterator():
   try:
     next(make_js_generator(range(0,5)))
     assert (False)
-  except Exception as e:
-    assert str(type(e)) == "<class 'pythonmonkey.SpiderMonkeyError'>"
-    assert str(e).__contains__("'range' object is not an iterator")
+  except pm.SpiderMonkeyError as e:
+    assert "'range' object is not an iterator" in str(e)