fn sign_keychain<FEN: FoundryEvmNetwork>(
state: &mut Cheatcodes<FEN>,
private_key: &U256,
account: &Address,
digest: &B256,
) -> Resultfn sign_keychain<FEN: FoundryEvmNetwork>(
state: &mut Cheatcodes<FEN>,
private_key: &U256,
account: &Address,
digest: &B256,
) -> Result