I actually solved the problem myself.
p1 = Polygon(ring.coords)
p2 = Polygon(ring2.coords)
to make polygons from my rings. then I create an array with those polygons. merge them with cascaded_union and create a LinearRing from the new polygon.
pols = [p1, p2]
new_pol = ops.cascaded_union(pols)
new_ring = LinearRing(new_pol.exterior.coords)