code: def delete_annotations(event, key, namespace=None, matchfunc=None):
      
      if matchfunc is None:
          matchfunc = _is_equal
      if isinstance(key, Exception):
          key = _error_repr(key)
      newanns = [ann for ann in event.get("_humilis", {}).get("annotation", [])
                 if not (matchfunc(key, ann["key"]) and
                     (namespace is None or ann.get("namespace") == namespace))]
      replace_event_annotations(event, newanns)
docs: Delete all event annotations with a matching key.