Cairo/Nile: Testing the proxy upgrade feature, but my tests fail with the error message TypeError: int() can't convert non-string with explicit base.

Hey there!

I am using the Oz Nile framework for smart contract development on Starknet. More specifically, I am testing the proxy upgrade feature, but my tests fail with the error message TypeError: int() can't convert non-string with explicit base. This happens when nile.signer tries to sign a transaction. Here's the snippet in the stack trace below.

def sign_transaction(self, sender, calls, nonce, max_fee):
        """Sign a transaction for an Account."""
        (call_array, calldata) = from_call_to_call_array(calls)
        message_hash = get_transaction_hash(
>           int(sender, 16), call_array, calldata, nonce, int(max_fee)
        )

Some relevant info: cairo-lang==0.10.0 cairo-nile==0.8.2 openzeppelin-cairo-contracts==0.4.0b pytest==7.1.2 python=3.9

This question was originally posted on StarkNet Discord