code: def successful(self):
      # Python 3.6 raise assertion error
      if not self.ready():
          raise ValueError()
  
      return self.future.successful()
  
imports: import logging
  import traceback
  from orion.core.utils.module_import import ImportOptional
  from orion.executor.base import AsyncException, AsyncResult, BaseExecutor, ExecutorClosed, Future
label_desc: Use image node_id 5 for calling the _Future obj's underlying member method code with example usage: obj.successful() and returns: self