Return a new ``<p:sp>`` element tree configured as a base textbox
        shape.

def new_textbox_sp(id_, name, left, top, width, height):
        """
        Return a new ``<p:sp>`` element tree configured as a base textbox
        shape.
        """
        tmpl = CT_Shape._textbox_sp_tmpl()
        xml = tmpl % (id_, name, left, top, width, height)
        sp = parse_xml(xml)
        return sp