code: def initialise(self):
      if self.initialised != -1:
          return
  
      db = self.get_db()
      if db is None:
          self.initialised = 0  # failure
          return
  
      db.connect()
      tz_db_proxy.initialize(db)
      db.create_tables([_KV])
      self.initialised = 1
  
imports: import peewee
  from threading import Lock
  import os
  import appdirs
  import atexit
  import datetime
  import pickle
  from .utils import get_yf_logger
label_desc: Use image node_id 3 for calling the _TzCache obj's underlying member method code with example usage: obj.initialise() without return types