class_docstr: The dashboard object!
code: def update_thumbnail(self) -> None:
      cache_dashboard_thumbnail.delay(
          current_user=get_current_user(),
          dashboard_id=self.id,
          force=True,
      )
  
imports: from __future__ import annotations
  import json
  import logging
  import uuid
  from collections import defaultdict
  from typing import Any, Callable
  import sqlalchemy
  from flask_appbuilder import Model
  from flask_appbuilder.models.decorators import renders
  from flask_appbuilder.security.sqla.models import User
  from markupsafe import escape, Markup
  from sqlalchemy import Boolean, Column, ForeignKey, Integer, MetaData, String, Table, Text, UniqueConstraint
  from sqlalchemy.engine.base import Connection
  from sqlalchemy.orm import relationship, sessionmaker, subqueryload
  from sqlalchemy.orm.mapper import Mapper
  from sqlalchemy.sql import join, select
  from sqlalchemy.sql.elements import BinaryExpression
  from superset import app, db, is_feature_enabled, security_manager
  from superset.connectors.sqla.models import BaseDatasource, SqlaTable
  from superset.daos.datasource import DatasourceDAO
  from superset.extensions import cache_manager
  from superset.models.helpers import AuditMixinNullable, ImportExportMixin
  from superset.models.slice import Slice
  from superset.models.user_attributes import UserAttribute
  from superset.tasks.thumbnails import cache_dashboard_thumbnail
  from superset.tasks.utils import get_current_user
  from superset.thumbnails.digest import get_dashboard_digest
  from superset.utils import core
  from superset.utils.decorators import debounce
label_desc: Use image node_id 17 for calling the Dashboard obj's underlying member method code with example usage: obj.update_thumbnail() without return types