def mine_chain(self):
        self.log.info('Create some old blocks')
        address = self.nodes[0].get_deterministic_priv_key().address
        for t in range(TIME_GENESIS_BLOCK, TIME_GENESIS_BLOCK + 200 * 600, 600):
            # ten-minute steps from genesis block time
            self.nodes[0].setmocktime(t)
            self.nodes[0].generatetoaddress(1, address)
        assert_equal(self.nodes[0].getblockchaininfo()['blocks'], 200)