Print object information using a namedtuple and a format pattern.

def _prtstr(self, obj, dashes):
        """Print object information using a namedtuple and a format pattern."""
        self.prt.write('{DASHES:{N}}'.format(
            DASHES=self.fmt_dashes.format(DASHES=dashes, ID=obj.item_id),
            N=self.dash_len))
        self.prt.write("{INFO}\n".format(INFO=str(obj)))