function validatorsUpdate(
    address[] memory newValidators,
    uint[] memory signers,
    uint8[] memory vs,
    bytes32[] memory rs,
    bytes32[] memory ss
) public {
    // validators should not sign a set that is equal to the current one to prevent spamming
    bytes32 message = keccak256(abi.encodePacked(newValidators, _nonce, _contractId, "V"));
    validateSignatures(message, signers, vs, rs, ss);
    _validators = newValidators;
    _nonce += 1;
    emit newValidatorsEvent(newValidators);
}