code: def market_order(self, direction, quantity, **kwargs):
          
          kwargs['limit_price'] = 0
          kwargs['order_type'] = "MARKET"
          self.parent.order(direction.upper(), self, quantity=quantity, **kwargs)
docs: Shortcut for ``instrument.order(...)`` and accepts all of its
          `optional parameters <#qtpylib.instrument.Instrument.order>`_
  
          :Parameters:
              direction : string
                  Order Type (BUY/SELL, EXIT/FLATTEN)
              quantity : int
                  Order quantity