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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 is_new_namespace_preorder( self, namespace_id_hash, lastblock=None ):
 """ Given a namespace preorder hash, determine whether or not is is unseen before. """

        if lastblock is None:
            lastblock = self.lastblock 

        preorder = namedb_get_namespace_preorder( self.db, namespace_id_hash, lastblock )
        if preorder is not None:
            return False 
        else:
            return True