An internal helper for the representation methods

def _get_attrs(self):
        """An internal helper for the representation methods"""
        attrs = []
        attrs.append(("N Blocks", self.n_blocks, "{}"))
        bds = self.bounds
        attrs.append(("X Bounds", (bds[0], bds[1]), "{:.3f}, {:.3f}"))
        attrs.append(("Y Bounds", (bds[2], bds[3]), "{:.3f}, {:.3f}"))
        attrs.append(("Z Bounds", (bds[4], bds[5]), "{:.3f}, {:.3f}"))
        return attrs