Skill Level Rank Bonus Calculation

def skill_level(self, rank):
    '''
    RANK += RANK BONUS
    --------------------------
    1 to 9 += 3
    10 to 19 += 2
    20 to 29 += 2
    30 to 39 += 1
    40 to 49 += 1
    50 to 59 += 0.5
    60 to 69 += 0.5
    70 to 79 += 0.5
    80 to 89 += 0.5
    90 to 100 += 0.5
    101 to 150 += 0.25
    151 to 200 += 0.125
    201 to 500 += 0.0625
    501 to 1,000 += 0.025
    1,001 to infinity += 0.01
    '''
    #Temp Values
    rb = 0
    rank = 100

    #Formula
    if rank:
        r = range(rank) if rank < 9 else range(9)
        for i in r:
            rb += 3
        if rank >= 10:
            r = range(rank - 9) if rank < 19 else range(10)
            for i in r:
                rb += 2
            if rank >= 20:
                r = range(rank - 19) if rank < 29 else range(10)
                for i in r:
                    rb += 2
                if rank >= 30:
                    r = range(rank - 29) if rank < 39 else range(10)
                    for i in r:
                        rb += 1
                    if rank >= 40:
                        r = range(rank - 39) if rank < 49 else range(10)
                        for i in r:
                            rb += 1
                        if rank >= 50:
                            r = range(rank - 49) if rank < 59 else range(10)
                            for i in r:
                                rb += 0.5
                            if rank >= 60:
                                r = range(rank - 59) if rank < 69 else range(10)
                                for i in r:
                                    rb += 0.5
                                if rank >= 70:
                                    r = range(rank - 69) if rank < 79 else range(10)
                                    for i in r:
                                        rb += 0.5
                                    if rank >= 80:
                                        r = range(rank - 79) if rank < 89 else range(10)
                                        for i in r:
                                            rb += 0.5
                                        if rank >= 90:
                                            r = range(rank - 89) if rank < 100 else range(11)
                                            for i in r:
                                                rb += 0.5
                                            if rank >= 101:
                                                r = range(rank - 100) if rank < 150 else range(50)
                                                for i in r:
                                                    rb += 0.25
                                                if rank >= 151:
                                                    r = range(rank - 150) if rank < 200 else range(50)
                                                    for i in r:
                                                        rb += 0.125
                                                    if rank >= 201:
                                                        r = range(rank - 200) if rank < 500 else range(300)
                                                        for i in r:
                                                            rb += 0.0625
                                                        if rank >= 501:
                                                            r = range(rank - 500) if rank < 1000 else range(500)
                                                            for i in r:
                                                                rb += 0.025
                                                            if rank >= 1001:
                                                                r = range(rank - 1000)
                                                                for i in r:
                                                                    rb += 0.01
        return rb # Return if any rank.
    return None # Return if no rank.