old_contents: 
  from .market_calendar import MarketCalendar
  
  def get_calendar(name, open_time=None, close_time=None):
      """
      Retrieves an instance of an MarketCalendar whose name is given.
  
      :param name: The name of the MarketCalendar to be retrieved.
      :param open_time: Market open time override as datetime.time object. If None then default is used.
      :param close_time: Market close time override as datetime.time object. If None then default is used.
      :return: MarketCalendar of the desired calendar.
      """
      return MarketCalendar.factory(name, open_time=open_time, close_time=close_time)
  
  
  def get_calendar_names():
      """All Market Calendar names and aliases that can be used in "factory"
      :return: list(str)
      """
      return MarketCalendar.calendar_names()
  
new_contents: 
  from .market_calendar import MarketCalendar
  
  
  def get_calendar(name, open_time=None, close_time=None):
      """
      Retrieves an instance of an MarketCalendar whose name is given.
  
      :param name: The name of the MarketCalendar to be retrieved.
      :param open_time: Market open time override as datetime.time object. If None then default is used.
      :param close_time: Market close time override as datetime.time object. If None then default is used.
      :return: MarketCalendar of the desired calendar.
      """
      return MarketCalendar.factory(name, open_time=open_time, close_time=close_time)
  
  
  def get_calendar_names():
      """All Market Calendar names and aliases that can be used in "factory"
      :return: list(str)
      """
      return MarketCalendar.calendar_names()
  
subject: add blank line