class_docstr: `Base` is the root class for all graphical class, it provides
  part of the initialization parameters and common methods
code: def _prepare_render(self):
      self.json_contents = self.dump_options()
      self._use_theme()
  
      self._render_cache.clear()
      if self.render_options.get("embed_js"):
          self._render_cache[
              "javascript"
          ] = self.load_javascript().load_javascript_contents()
  
imports: import datetime
  import uuid
  import simplejson
  from jinja2 import Environment
  from ..commons import utils
  from ..globals import CurrentConfig, RenderType, ThemeType
  from ..options import InitOpts, RenderOpts
  from ..options.global_options import AnimationOpts
  from ..options.series_options import BasicOpts
  from ..render import engine
  from ..types import Optional, Sequence, Union
  from .mixins import ChartMixin
label_desc: Use image node_id 10 for calling the Base obj's underlying member method code with example usage: obj._prepare_render() without return types