Harmonic series and square root of numbers - Newton's method - Afson.py

if income <0:
    rate = 0.00
else:
    if income < 8.925:
        rate = 0.10
    else:
        if income < 36.250:
            rate = 0.15
            else:
                if income < 87.850:
                    rate = 0.23
                    if income < 183250:
                        rate =  0.28
                        if income < 398350:
                            rate < 0.33
                            if income < 400000:
                                rate = 0.35
                                else:
                                    rate = 0.396