code: def start_session(self):
      return self._start_session
  
imports: from functools import partial
  import logbook
  import pandas
  from pandas.tslib import normalize_date
  from six import string_types
  from sqlalchemy import create_engine
  from catalyst.assets import AssetDBWriter, AssetFinder
  from catalyst.assets.continuous_futures import CHAIN_PREDICATES
  from catalyst.data.loader import load_market_data
  from catalyst.utils.calendars import get_calendar
  from catalyst.utils.memoize import remember_last
  from catalyst.constants import LOG_LEVEL
label_desc: Use image node_id 8 for calling the SimulationParameters obj's underlying member method code with example usage: obj.start_session() and returns: self