code: def call_purge_doc(cls, kb_app, sphinx_app: Sphinx,
                         sphinx_env: BuildEnvironment,
                         docname: str):
          
  
          for callback in EventAction.get_callbacks(kb_app, SphinxEvent.EPD):
              callback(kb_app, sphinx_app, sphinx_env, docname)
docs: On env-purge-doc, do callbacks