async def fetch_trades(self, symbol, since=None, limit=None, params={}):
    (await self.load_markets())
    market = self.market(symbol)
    request = {'symbol': market['id']}
    if (since is not None):
        request['since'] = since
    if (limit is not None):
        request['limit'] = limit
    response = (await self.marketGetTrades(self.extend(request, params)))
    return self.parse_trades(response, market, since, limit)
async def fetch_trades(self, symbol, since=None, limit=None, params={}):
    (await self.load_markets())
    market = self.market(symbol)
    request = {'symbol': market['id']}
    if (since is not None):
        request['since'] = since
    if (limit is not None):
        request['limit'] = limit
    response = (await self.marketGetTrades(self.extend(request, params)))
    return self.parse_trades(response, market, since, limit)