async def fetch_bids_asks(self, symbols=None, params={}):
    (await self.load_markets())
    response = (await self.marketGetDepth(params))
    return self.parse_tickers(response, symbols)
async def fetch_bids_asks(self, symbols=None, params={}):
    (await self.load_markets())
    response = (await self.marketGetDepth(params))
    return self.parse_tickers(response, symbols)