'Constructor.
Args:
initializer: A string or another RDFURN.
age: The age of this entry.'

def __init__(self, initializer=None, age=None):

    if isinstance(initializer, RDFURN):
        self._string_urn = initializer.Path()
        super(RDFURN, self).__init__(None, age=age)
        return
    super(RDFURN, self).__init__(initializer=initializer, age=age)
    if ((self._value is None) and (initializer is not None)):
        self.ParseFromString(initializer)
