Improve code clarity a bit.

Lib/collections.py

@@ -41,7 +41,8 @@ class OrderedDict(dict, MutableMapping):
             self.__root
         except AttributeError:
             self.__root = root = [None, None, None]     # sentinel node
-            PREV, NEXT = 0, 1
+            PREV = 0
+            NEXT = 1
             root[PREV] = root[NEXT] = root
             self.__map = {}
         self.update(*args, **kwds)
@@ -51,7 +52,8 @@ class OrderedDict(dict, MutableMapping):
         # Setting a new item creates a new link which goes at the end of the linked
         # list, and the inherited dictionary is updated with the new key/value pair.
         if key not in self:
-            PREV, NEXT = 0, 1
+            PREV = 0
+            NEXT = 1
             root = self.__root
             last = root[PREV]
             last[NEXT] = root[PREV] = self.__map[key] = [last, root, key]
@@ -62,7 +64,8 @@ class OrderedDict(dict, MutableMapping):
         # Deleting an existing item uses self.__map to find the link which is
         # then removed by updating the links in the predecessor and successor nodes.
         dict.__delitem__(self, key)
-        PREV, NEXT = 0, 1
+        PREV = 0
+        NEXT = 1
         link = self.__map.pop(key)
         link[PREV][NEXT] = link[NEXT]
         link[NEXT][PREV] = link[PREV]
@@ -70,7 +73,8 @@ class OrderedDict(dict, MutableMapping):
     def __iter__(self):
         'od.__iter__() <==> iter(od)'
         # Traverse the linked list in order.
-        NEXT, KEY = 1, 2
+        NEXT = 1
+        KEY = 2
         root = self.__root
         curr = root[NEXT]
         while curr is not root:
@@ -80,7 +84,8 @@ class OrderedDict(dict, MutableMapping):
     def __reversed__(self):
         'od.__reversed__() <==> reversed(od)'
         # Traverse the linked list in reverse order.
-        PREV, KEY = 0, 2
+        PREV = 0
+        KEY = 2
         root = self.__root
         curr = root[PREV]
         while curr is not root: