Fetch Okex Futures

# -*- coding: utf-8 -*-

import os
import sys
import time
import ccxt  # noqa: E402
exchange = ccxt.okex()
exchange.load_markets()
for symbol in exchange.markets:
   market = exchange.markets[symbol]
   if market['future']:
       print('----------------------------------------------------')
       print(symbol, exchange.fetchTicker(symbol))
       time.sleep(exchange.rateLimit / 1000)