code: def book(self, symbol='btcusd', limit_bids=0, limit_asks=0):
          
          url = self.base_url + '/v1/book/' + symbol
          params = {
              'limit_bids': limit_bids,
              'limit_asks': limit_asks
          }
  
          return requests.get(url, params)
docs: Send a request to get the public order book, return the response.
  
          Arguments:
          symbol -- currency symbol (default 'btcusd')
          limit_bids -- limit the number of bids returned (default 0)
          limit_asks -- limit the number of asks returned (default 0)