code: def _get_graph(self, ctx, bundle, extensions, caller=None):
          
          request = ctx.get('request')
          if request is None:
              request = get_current_request()
          if ':' in bundle:
              config_name, bundle = bundle.split(':')
          else:
              config_name = 'DEFAULT'
          webpack = request.webpack(config_name)
          assets = (caller(a) for a in webpack.get_bundle(bundle, extensions))
          return ''.join(assets)
docs: Run a graph and render the tag contents for each output