# Absolute value of a polynomial

How can I generate a random polynomial with two variables x, y of fix degree which is not of type : `<type 'sage.rings.polynomial.multi_polynomial_libsingular.MPolynomial_libsingular'`

?

I would like to compute the absolute value of this polynomial, but when I generate it using :
```
R = ZZ['x','y'];
F = R.random_element(4, 1000)
```

for example, I get : `TypeError: bad operand type for abs(): 'sage.rings.polynomial.multi_polynomial_libsingular.MPolynomial_libsingular'`

What would be a good alternative to get |F(x,y)| ? Thanks