class_docstr: A mixin class to provide an interface for registering and
  triggering event callbacks on the Python side.
class_docstr_tok: ["A","mixin","class","to","provide","an","interface","for","registering","and","triggering","event","callbacks","on","the","Python","side","."]
code: def __init__(self, *args: Any, **kw: Any) -> None:
      super().__init__(*args, **kw)
      self._event_callbacks = defaultdict(list)
  
file_path: bokeh/src/bokeh/util/callback_manager.py
imports: from __future__ import annotations
  import logging
  from collections import defaultdict
  from inspect import signature
  from typing import TYPE_CHECKING, Any, Callable, Sequence, Union, cast
  from ..events import Event, ModelEvent
  from ..util.functions import get_param_info
label_desc: Use image node_id 1 to create a new EventCallbackManager object  with example: obj = EventCallbackManager()