code: def _get_scalars_plugin(self):
      
      if scalars_metadata.PLUGIN_NAME in self._plugin_name_to_instance:
        # The plugin is registered.
        return self._plugin_name_to_instance[scalars_metadata.PLUGIN_NAME]
      # The plugin is not yet registered.
      return None
docs: Tries to get the scalars plugin.
  
      Returns:
        The scalars plugin. Or None if it is not yet registered.