def crl(self):
        """
        Returns up to date CRL of this CA
        """
        revoked_certs = self.get_revoked_certs()
        crl = crypto.CRL()
        now_str = timezone.now().strftime(generalized_time)
        for cert in revoked_certs:
            revoked = crypto.Revoked()
            revoked.set_serial(bytes_compat(cert.serial_number))
            revoked.set_reason(b'unspecified')
            revoked.set_rev_date(bytes_compat(now_str))
            crl.add_revoked(revoked)
        return crl.export(self.x509, self.pkey, days=1, digest=b'sha256')
Returns up to date CRL of this CA