library LiquidityMath {
    /// @notice Add a signed liquidity delta to liquidity and revert if it overflows or underflows
    /// @param x The liquidity before change
    /// @param y The delta by which liquidity should be changed
    /// @return z The liquidity delta
    function addDelta(uint128 x, uint128 y) internal pure returns (uint128 z) {
        require((z = x + uint128(y)) >= x, 'LA');
    }
}
/// @title Math library for liquidity
function addDelta(uint128 x, uint128 y) internal pure returns (uint128 z) {
        require((z = x + uint128(y)) >= x, 'LA');
    }
/// @notice Add a signed liquidity delta to liquidity and revert if it overflows or underflows
/// @param x The liquidity before change
/// @param y The delta by which liquidity should be changed
/// @return z The liquidity delta