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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 import_reference(self, ):
 """Import the currently loaded reference This will also update the status to :data:`Reftrack.IMPORTED`. :returns: None :rtype: None :raises: :class:`ReftrackIntegrityError` """

        assert self.status() in (self.LOADED, self.UNLOADED),\
            "There is no reference for this entity."
        refobjinter = self.get_refobjinter()
        refobjinter.import_reference(self.get_refobj())
        self.set_status(self.IMPORTED)
        self.update_restrictions()
        for c in self.get_all_children():
            c.update_restrictions()
        self.emit_data_changed()