def METHOD_NAME():
    """
    >>> import ZODB.tests.util
    >>> from persistent.wref import PersistentWeakKeyDictionary
    >>> key = ZODB.tests.util.P("key")
    >>> missing = ZODB.tests.util.P("missing")
    >>> d = PersistentWeakKeyDictionary([(key, 1)])
    >>> d.get(key)
    1
    >>> d.get(missing)
    >>> d.get(missing, 12)
    12
    """