docs: def __render(self, context, **kwargs):
          """
          Render template.
  
          :param context: A dict or dict-like object to instantiate given
              template file
          :param kwargs: Keyword arguments passed to the template engine to
              render templates with specific features enabled.
  
          :return: Rendered string
          """
          # Not pass both searchList and namespaces.
          kwargs["namespaces"] = [context, ] + kwargs.get("namespaces", []) \
                                             + kwargs.get("searchList", [])
          kwargs["searchList"] = None
  
          # TODO:
          # if at_paths is not None:
          #    paths = at_paths + self._engine_valid_opts.get(..., [])
          #    ...
          kwargs = self.filter_options(kwargs, self.engine_valid_options())
          self.engine_options.update(kwargs)
  
          return render_impl(**self.engine_options)