interface ISignaturesValidator {
    /**
     * @dev Returns the EIP712 domain separator.
     */
    function getDomainSeparator() external view returns (bytes32);

    /**
     * @dev Returns the next nonce used by an address to sign messages.
     */
    function getNextNonce(address user) external view returns (uint256);
}
/**
 * @dev Interface for the SignatureValidator helper, used to support meta-transactions.
 */
function getDomainSeparator() external view returns (bytes32);

/**
 * @dev Returns the EIP712 domain separator.
 */