class_docstr: Class encapsulating an order to be placed at the current market price.
code: def __init__(self, exchange=None):
      self._exchange = exchange
  
imports: import abc
  from numpy import isfinite
  from six import with_metaclass
  from catalyst.errors import BadOrderParameters
label_desc: Use image node_id 1 to create a new MarketOrder object from inherited base classes: ExecutionStyle with example: obj = MarketOrder(exchange)