class_docstr: Encapsulation of a caching system that is currently backed by the filesystem
  
  The "state" of a StreamQuery execution is encapsulated by
code: def __init__(self, logger=None):
      self._logger = logger
  
      self._data = {}
  
file_path: streamalert/streamalert/scheduled_queries/state/state_manager.py
imports: from datetime import datetime
label_desc: Use image node_id 1 to create a new StateManager object  with example: obj = StateManager(logger)