Coefficient overflow in PolynomialRing()

edit

I'm trying to create a multivariate polynomial, whose coefficients are elements of Integers(2**256).

The problem is that trying to set any coefficient larger than 2**63 raises OverflowError: Python int too large to convert to C long. I think this is because of the underlying interface to singular, even though singular apparently supports bigints. Is there any workaround to this?