class_docstr: Object to render charts as HTML, with a unique output div each time
code: def __call__(self, spec: dict, **metadata) -> Dict[str, str]:
      kwargs = self.kwargs.copy()
      kwargs.update(metadata)
      # To get proper return value type, would need to write complex
      # overload signatures for spec_to_mimebundle based on `format`
      return spec_to_mimebundle(  # type: ignore[return-value]
          spec, format="html", output_div=self.output_div, **kwargs
      )
  
imports: import json
  import pkgutil
  import textwrap
  from typing import Callable, Dict, Optional, Tuple, Any, Union
  import uuid
  from ._vegafusion_data import compile_with_vegafusion, using_vegafusion
  from .plugin_registry import PluginRegistry, PluginEnabler
  from .mimebundle import spec_to_mimebundle
  from .schemapi import validate_jsonschema
label_desc: Use image node_id 3 for calling the HTMLRenderer obj's underlying member method code with example usage: obj.__call__(spec) and returns: spec_to_mimebundle