def __setitem__(self, key, value):
if key in self:
- self.inverse[self[key]].remove(key)
+ old_value = self[key]
+ self.inverse[old_value].remove(key)
super().__setitem__(key, value)
self.inverse.setdefault(value, []).append(key)
def __delitem__(self, key):
- self.inverse.setdefault(self[key], []).remove(key)
- if self[key] in self.inverse and not self.inverse[self[key]]:
- del self.inverse[self[key]]
+ value = self[key]
+ self.inverse.setdefault(value, []).remove(key)
+ if value in self.inverse and not self.inverse[value]:
+ del self.inverse[value]
super().__delitem__(key)