Função do python que valida cnpjs usando as normas do dataprev. (http://sa.previdencia.gov.br/site/2015/07/rgrv_RegrasValidacao.pdf)

validate_cnpj.py

def validate_cnpj(cnpj):
    if len(cnpj) != 14 or len(set(cnpj)) == 1:
        return False

    def calculate_verifier(digits,multipliers):
        multiplied_pairwise = [(int(x)*int(y)) for x,y in zip(digits,multipliers)]
        sum_ = sum(multiplied_pairwise)
        modulo = sum_ % 11
        verifier = 0 if modulo < 2 else (11 - modulo)
        return str(verifier)

    verifiers = cnpj[12:]
    first_verifier = calculate_verifier(cnpj[:12],'543298765432')
    second_verifier = calculate_verifier(cnpj[:12] + first_verifier,'6543298765432')

    if f'{first_verifier}{second_verifier}' == verifiers:
        return True
    return False