def fetch_l2_order_book(self, symbol, limit=None, params={}):
    orderbook = self.fetch_order_book(symbol, limit, params)
    return self.extend(orderbook, {'bids': self.sort_by(self.aggregate(orderbook['bids']), 0, True), 'asks': self.sort_by(self.aggregate(orderbook['asks']), 0)})
def fetch_l2_order_book(self, symbol, limit=None, params={}):
    orderbook = self.fetch_order_book(symbol, limit, params)
    return self.extend(orderbook, {'bids': self.sort_by(self.aggregate(orderbook['bids']), 0, True), 'asks': self.sort_by(self.aggregate(orderbook['asks']), 0)})