Odoo 13 CE

hello i have a problem with pyhton code on salary rukle; can you help me please?

I inserted this code in the wage rule to have a deduction on the salary anace. when I calculate the pay slip I receive an error mesage that the code is erroneous.

how to do?

condition code  : result = employee.get_Advance_Salary (employee.id, payslip.date_from, payslip.date_to ) > 0

calcul code : result = -employee.get_Advance_Salary (employee.id, payslip.date_from, payslip.date_to )