def METHOD_NAME(self, request: Optional[IRequest]) -> "Flattenable":
    """
    Implement L{IRenderable} to allow one L{Element} to be embedded in
    another's template or rendering output.
    (This will simply load the template from the C{loader}; when used in a
    template, the flattening engine will keep track of this object
    separately as the object to lookup renderers on and call
    L{Element.renderer} to look them up.  The resulting object from this
    method is not directly associated with this L{Element}.)
    """
    loader = self.loader
    if loader is None:
        raise MissingTemplateLoader(self)
    return loader.load()