Approaching python3 compatibility
--HG--
branch : trunk
diff --git a/jinja2/sandbox.py b/jinja2/sandbox.py
index 9887310..7497195 100644
--- a/jinja2/sandbox.py
+++ b/jinja2/sandbox.py
@@ -37,13 +37,21 @@
warnings.filterwarnings('ignore', 'the sets module', DeprecationWarning,
module='jinja2.sandbox')
-
from collections import deque
-from UserDict import UserDict, DictMixin
-from UserList import UserList
+
_mutable_set_types = (set,)
-_mutable_mapping_types = (UserDict, DictMixin, dict)
-_mutable_sequence_types = (UserList, list)
+_mutable_mapping_types = (dict,)
+_mutable_sequence_types = (list,)
+
+
+# on python 2.x we can register the user collection types
+try:
+ from UserDict import UserDict, DictMixin
+ from UserList import UserList
+ _mutable_mapping_types += (UserDict, DictMixin)
+ _mutable_set_types += (UserList,)
+except ImportError:
+ pass
# if sets is still available, register the mutable set from there as well
try: