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 set(self, key, value):
      self._data[key] = value
  
file_path: streamalert/streamalert/scheduled_queries/state/state_manager.py
imports: from datetime import datetime
label_desc: Use image node_id 2 for calling the StateManager obj's underlying member method code with example usage: obj.set(key, value) without return types