def __delitem__(self, key):
"""
This is not O(1) because we have to traverse the heap to find the item
to delete and then reheapify!
"""
value = obsdict.pop(self, key)
cmpval = self._sortkey(value) if self._sortkey else value
heapitem = (cmpval, key)
self._heap.remove(heapitem)
heapify(self._heap)
def popitem(self):
"""
Removes and returns the (key, value) pair with smallest sorted value
if available.
"""
if not self:
raise KeyError
removed = heappop(self._heap)
key = removed[1]
value = obsdict.pop(self, key)
return key, value
