code: def open_time(self):
      return time(0)
  
file_path: catalyst/catalyst/utils/calendars/exchange_calendar_open.py
imports: from datetime import time
  from pytz import timezone
  from pandas import Timestamp
  from pandas.tseries.offsets import DateOffset
  from catalyst.utils.memoize import lazyval
  from .trading_calendar import TradingCalendar
label_desc: Use image node_id 3 for calling the OpenExchangeCalendar obj's underlying member method code with example usage: obj.open_time() and returns: time