Since uint256 cannot be negative, the check _amount < 0 is inherently impossible. This leaves only the possibility of _amount being equal to zero as a valid check.
https://github.com/code-423n4/2024-04-renzo/blob/519e518f2d8dec9acf6482b84a181e403070d22d/contracts/Bridge/Connext/integration/LockboxAdapterBlast.sol#L65
