class_docstr: Lightweight class that maintains a basic queue of operations, in addition
  to metadata annotations.
docstr: Adds this instance to the global list of active contexts.
  
  Returns:
      AnnotatedQueue: this instance
docstr_tok: ["Adds","this","instance","to","the","global","list","of","active","contexts",".","Returns",":","AnnotatedQueue",":","this","instance"]
code: def __enter__(self):
      """Adds this instance to the global list of active contexts.
  
      Returns:
          AnnotatedQueue: this instance
      """
      AnnotatedQueue._lock.acquire()
      QueuingManager.add_active_queue(self)
  
      return self
  
imports: import copy
  from collections import OrderedDict
  from contextlib import contextmanager
  from threading import RLock
  from typing import Optional
label_desc: Use image node_id 1 for calling the AnnotatedQueue obj's underlying member method code with example usage: obj.__enter__() and returns: self