let keyset_info = self
            .core_client(mint_url)?
            .keyset_info(keyset_id_parsed)
            .await
            .map_err(|e| {
                log::error!("Error getting keyset info from {mint_url}: {e}");
                Error::KeyClient
            })?;

        let ys = token
            .proofs(&[keyset_info])
            .map_err(|_| Error::InvalidToken)?
            .ys()
            .map_err(|_| Error::PubKey)?;

        let proof_states = self
            .core_client(mint_url)?
            .check_state(ys)
            .await
            .map_err(|e| {
                log::error!("Error checking if proofs are spent at {mint_url}: {e}");
                Error::SwapClient
            })?;