def __contains__(self, id):
        return self._key_for(id) in self._messages
Detect list del events and emit change events.
dataset/ETHPy150Open jbalogh/glow/vendor/lib/python/babel/messages/catalog.py/Catalog.__contains__--crossover with--dataset/ETHPy150Open openstack/sahara/sahara/db/sqlalchemy/types.py/MutableList.__delitem__