def test_Domain_unify_with_symbols():
    raises(UnificationFailed, (lambda : ZZ[(x, y)].unify_with_symbols(ZZ, (y, z))))
    raises(UnificationFailed, (lambda : ZZ.unify_with_symbols(ZZ[(x, y)], (y, z))))
def test_Domain_unify_with_symbols():
    raises(UnificationFailed, (lambda : ZZ[(x, y)].unify_with_symbols(ZZ, (y, z))))
    raises(UnificationFailed, (lambda : ZZ.unify_with_symbols(ZZ[(x, y)], (y, z))))