class_docstr: Class used to define an AirflowPluginSource.
class_docstr_tok: ["Class","used","to","define","an","AirflowPluginSource","."]
code: def __html__(self):
      raise NotImplementedError
  
imports: from __future__ import annotations
  import importlib
  import importlib.machinery
  import importlib.util
  import inspect
  import logging
  import os
  import sys
  import types
  from pathlib import Path
  from typing import TYPE_CHECKING, Any, Iterable
  from airflow import settings
  from airflow.utils.entry_points import entry_points_with_dist
  from airflow.utils.file import find_path_from_directory
  from airflow.utils.module_loading import import_string, qualname
label_desc: Use image node_id 2 for calling the AirflowPluginSource obj's underlying member method code with example usage: obj.__html__() without return types