Renders the given element to string.

        :param element: a element to be rendered.
        :returns: the output string or any values.

def render(self, element):
        """Renders the given element to string.

        :param element: a element to be rendered.
        :returns: the output string or any values.
        """
        # Store the root node to provide some context to render functions
        if not self.root_node:
            self.root_node = element
        render_func = getattr(
            self, self._cls_to_func_name(element.__class__), None)
        if not render_func:
            render_func = self.render_children
        return render_func(element)