'Yields RDFURNs of all the children of this object.
Args:
limit: Total number of items we will attempt to retrieve.
age: The age of the items to retrieve. Should be one of ALL_TIMES,
NEWEST_TIME or a range in microseconds.
Yields:
RDFURNs instances of each child.'

def ListChildren(self, limit=1000000, age=NEWEST_TIME):

    index_prefix = 'index:dir/'
    for (predicate, _, timestamp) in data_store.DB.ResolvePrefix(self.urn, index_prefix, token=self.token, timestamp=Factory.ParseAgeSpecification(age), limit=limit):
        urn = self.urn.Add(predicate[len(index_prefix):])
        urn.age = rdfvalue.RDFDatetime(timestamp)
        (yield urn)
