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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ListChildren(self, limit=None, age=NEWEST_TIME):
 """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. """

    # Just grab all the children from the index.
    for predicate, timestamp in data_store.DB.AFF4FetchChildren(
        self.urn, timestamp=Factory.ParseAgeSpecification(age), limit=limit):
      urn = self.urn.Add(predicate)
      urn.age = rdfvalue.RDFDatetime(timestamp)
      yield urn