cpf.py

def next_digit(value, base):
    return value + str(sum(int(a)*b for a,b in zip(value, base))%11%10)

def make_valid(value, ap2, base):
    return next_digit(next_digit(value, base), ap2+base)

def is_valid_cpf(cpf):
    return make_valid(cpf[:9], [0], [1,2,3,4,5,6,7,8,9]) == cpf

def is_valid_cnpj(cnpj):
    return make_valid(cnpj[:12], [5], [6,7,8,9,2,3,4,5,6,7,8,9]) == cnpj