'Check if the given entity subscribe to this channel
Args:
entity (str, Player or Object): The entity to return. If
a string, it assumed to be the key or the #dbref
of the entity.
Returns:
subscriber (Player, Object or None): The given
subscriber.'

def has(self, entity):

    if (self._cache is None):
        self._recache()
    return (entity in self._cache)
