class_docstr: The CalendarRollFinder calculates contract rolls based purely on the
  contract's auto close date.
class_docstr_tok: ["The","CalendarRollFinder","calculates","contract","rolls","based","purely","on","the","contract","'s","auto","close","date","."]
code: def __init__(self, trading_calendar, asset_finder):
      self.trading_calendar = trading_calendar
      self.asset_finder = asset_finder
  
file_path: zipline/zipline/assets/roll_finder.py
imports: from abc import ABCMeta, abstractmethod
  from six import with_metaclass
label_desc: Use image node_id 1 to create a new CalendarRollFinder object from inherited base classes: RollFinder with example: obj = CalendarRollFinder(trading_calendar, asset_finder)