def fetch_closed_orders(self, symbol=None, since=None, limit=None, params={}):
    return self.fetch_orders(symbol, since, limit, self.extend({'state': 'FILLED'}, params))
def fetch_closed_orders(self, symbol=None, since=None, limit=None, params={}):
    return self.fetch_orders(symbol, since, limit, self.extend({'state': 'FILLED'}, params))