def METHOD_NAME(self):
    if self.n:
        i = self.element_id.argsort()
        self.element_id = self.element_id[i]
        self.property_id = self.property_id[i]
        self.node_ids = self.node_ids[i, :]
        self.components = self.components[i, :]
        unique_eids = unique(self.element_id)
        if len(unique_eids) != len(self.element_id):
            raise RuntimeError('There are duplicate CDAMP1 IDs...')
        self._cards = []
    else:
        self.element_id = array([], dtype='int32')
        self.property_id = array([], dtype='int32')