docs: def get_orderbook(self):
          """Get orderbook for the instrument
  
          :Retruns:
              orderbook : dict
                  orderbook dict for the instrument
          """
          if self in self.parent.books.keys():
              return self.parent.books[self]
  
          return {
              "bid": [0], "bidsize": [0],
              "ask": [0], "asksize": [0]
          }