<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def start(st_reg_number):
 """Checks the number valiaty for the Sergipe state"""

    divisor = 11

    if len(st_reg_number) > 9:
        return False

    if len(st_reg_number) < 9:
        return False

    sum_total = 0
    peso = 9

    for i in range(len(st_reg_number)-1):
        sum_total = sum_total + int(st_reg_number[i]) * peso
        peso = peso - 1

    rest_division = sum_total % divisor
    digit = divisor - rest_division

    if digit == 10 or digit == 11:
        digit = 0

    return digit == int(st_reg_number[len(st_reg_number)-1])