forwader.getNonces() is not a function

I'm currently following this guide and am using the signer from their github.

From their file, they use forwarder.getNonce() but from what I can see, this function doesn't exist in their code. I've copied my smart contract to deploy just like their register.sol smart contract but my forwarder doesn't have the getNonce() function.

Am I missing something or has their ERC2771Forwarder changed?