diff --git a/pyqtgraph/ordereddict.py b/pyqtgraph/ordereddict.py
index 7242b506..fb37037f 100644
--- a/pyqtgraph/ordereddict.py
+++ b/pyqtgraph/ordereddict.py
@@ -20,108 +20,112 @@
 #     FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 #     OTHER DEALINGS IN THE SOFTWARE.
 
-from UserDict import DictMixin
+import sys
+if sys.version[0] > '2':
+    from collections import OrderedDict
+else:
+    from UserDict import DictMixin
 
-class OrderedDict(dict, DictMixin):
+    class OrderedDict(dict, DictMixin):
 
-    def __init__(self, *args, **kwds):
-        if len(args) > 1:
-            raise TypeError('expected at most 1 arguments, got %d' % len(args))
-        try:
-            self.__end
-        except AttributeError:
-            self.clear()
-        self.update(*args, **kwds)
+        def __init__(self, *args, **kwds):
+            if len(args) > 1:
+                raise TypeError('expected at most 1 arguments, got %d' % len(args))
+            try:
+                self.__end
+            except AttributeError:
+                self.clear()
+            self.update(*args, **kwds)
 
-    def clear(self):
-        self.__end = end = []
-        end += [None, end, end]         # sentinel node for doubly linked list
-        self.__map = {}                 # key --> [key, prev, next]
-        dict.clear(self)
+        def clear(self):
+            self.__end = end = []
+            end += [None, end, end]         # sentinel node for doubly linked list
+            self.__map = {}                 # key --> [key, prev, next]
+            dict.clear(self)
 
-    def __setitem__(self, key, value):
-        if key not in self:
+        def __setitem__(self, key, value):
+            if key not in self:
+                end = self.__end
+                curr = end[1]
+                curr[2] = end[1] = self.__map[key] = [key, curr, end]
+            dict.__setitem__(self, key, value)
+
+        def __delitem__(self, key):
+            dict.__delitem__(self, key)
+            key, prev, next = self.__map.pop(key)
+            prev[2] = next
+            next[1] = prev
+
+        def __iter__(self):
+            end = self.__end
+            curr = end[2]
+            while curr is not end:
+                yield curr[0]
+                curr = curr[2]
+
+        def __reversed__(self):
             end = self.__end
             curr = end[1]
-            curr[2] = end[1] = self.__map[key] = [key, curr, end]
-        dict.__setitem__(self, key, value)
+            while curr is not end:
+                yield curr[0]
+                curr = curr[1]
 
-    def __delitem__(self, key):
-        dict.__delitem__(self, key)
-        key, prev, next = self.__map.pop(key)
-        prev[2] = next
-        next[1] = prev
+        def popitem(self, last=True):
+            if not self:
+                raise KeyError('dictionary is empty')
+            if last:
+                key = reversed(self).next()
+            else:
+                key = iter(self).next()
+            value = self.pop(key)
+            return key, value
 
-    def __iter__(self):
-        end = self.__end
-        curr = end[2]
-        while curr is not end:
-            yield curr[0]
-            curr = curr[2]
+        def __reduce__(self):
+            items = [[k, self[k]] for k in self]
+            tmp = self.__map, self.__end
+            del self.__map, self.__end
+            inst_dict = vars(self).copy()
+            self.__map, self.__end = tmp
+            if inst_dict:
+                return (self.__class__, (items,), inst_dict)
+            return self.__class__, (items,)
 
-    def __reversed__(self):
-        end = self.__end
-        curr = end[1]
-        while curr is not end:
-            yield curr[0]
-            curr = curr[1]
+        def keys(self):
+            return list(self)
 
-    def popitem(self, last=True):
-        if not self:
-            raise KeyError('dictionary is empty')
-        if last:
-            key = reversed(self).next()
-        else:
-            key = iter(self).next()
-        value = self.pop(key)
-        return key, value
+        setdefault = DictMixin.setdefault
+        update = DictMixin.update
+        pop = DictMixin.pop
+        values = DictMixin.values
+        items = DictMixin.items
+        iterkeys = DictMixin.iterkeys
+        itervalues = DictMixin.itervalues
+        iteritems = DictMixin.iteritems
 
-    def __reduce__(self):
-        items = [[k, self[k]] for k in self]
-        tmp = self.__map, self.__end
-        del self.__map, self.__end
-        inst_dict = vars(self).copy()
-        self.__map, self.__end = tmp
-        if inst_dict:
-            return (self.__class__, (items,), inst_dict)
-        return self.__class__, (items,)
+        def __repr__(self):
+            if not self:
+                return '%s()' % (self.__class__.__name__,)
+            return '%s(%r)' % (self.__class__.__name__, self.items())
 
-    def keys(self):
-        return list(self)
+        def copy(self):
+            return self.__class__(self)
 
-    setdefault = DictMixin.setdefault
-    update = DictMixin.update
-    pop = DictMixin.pop
-    values = DictMixin.values
-    items = DictMixin.items
-    iterkeys = DictMixin.iterkeys
-    itervalues = DictMixin.itervalues
-    iteritems = DictMixin.iteritems
+        @classmethod
+        def fromkeys(cls, iterable, value=None):
+            d = cls()
+            for key in iterable:
+                d[key] = value
+            return d
 
-    def __repr__(self):
-        if not self:
-            return '%s()' % (self.__class__.__name__,)
-        return '%s(%r)' % (self.__class__.__name__, self.items())
-
-    def copy(self):
-        return self.__class__(self)
-
-    @classmethod
-    def fromkeys(cls, iterable, value=None):
-        d = cls()
-        for key in iterable:
-            d[key] = value
-        return d
-
-    def __eq__(self, other):
-        if isinstance(other, OrderedDict):
-            if len(self) != len(other):
-                return False
-            for p, q in  zip(self.items(), other.items()):
-                if p != q:
+        def __eq__(self, other):
+            if isinstance(other, OrderedDict):
+                if len(self) != len(other):
                     return False
-            return True
-        return dict.__eq__(self, other)
+                for p, q in  zip(self.items(), other.items()):
+                    if p != q:
+                        return False
+                return True
+            return dict.__eq__(self, other)
 
-    def __ne__(self, other):
-        return not self == other
+        def __ne__(self, other):
+            return not self == other