Get Grouper, given GO IDs and sections.

def _get_grprobj(self, goids, sections):
        """Get Grouper, given GO IDs and sections."""
        grprdflt = GrouperDflts(self.gosubdag, "goslim_generic.obo")
        hdrobj = HdrgosSections(self.gosubdag, grprdflt.hdrgos_dflt, sections)
        return Grouper("sections", goids, hdrobj, self.gosubdag)