+# OrderedDict class based on
+# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/107747
+# Licensed under the Python License
+class OrderedDict(dict):
+ def __init__(self):
+ self._keys = []
+ dict.__init__(self)
+
+ def __delitem__(self, key):
+ dict.__delitem__(self, key)
+ self._keys.remove(key)
+
+ def __setitem__(self, key, item):
+ dict.__setitem__(self, key, item)
+ if key not in self._keys: self._keys.append(key)
+
+ def clear(self):
+ dict.clear(self)
+ self._keys = []
+
+ def copy(self):
+ dict = dict.copy(self)
+ dict._keys = self._keys[:]
+ return dict
+
+ def items(self):
+ return zip(self._keys, self.values())
+
+ def keys(self):
+ return self._keys
+
+ def popitem(self):
+ try:
+ key = self._keys[-1]
+ except IndexError:
+ raise KeyError('dictionary is empty')
+
+ val = self[key]
+ del self[key]
+
+ return (key, val)
+
+ def setdefault(self, key, failobj = None):
+ dict.setdefault(self, key, failobj)
+ if key not in self._keys: self._keys.append(key)
+
+ def update(self, dict):
+ dict.update(self, dict)
+ for key in dict.keys():
+ if key not in self._keys: self._keys.append(key)
+
+ def values(self):
+ return map(self.get, self._keys)
+