docs: function getTransactionSuccess(web3, hash, callback) {
    const receiptInterval = setInterval(() => {
      web3.eth.getTransactionReceipt(hash, (receiptError, receipt) => {
        if (receiptError) {
          clearInterval(receiptInterval);
          return callback(`while getting receipt for hash '${hash}: ${receiptError}'`, false);
        }
  
        // this is probably wrong
        if (receipt.blockHash !== '0x') {
          clearInterval(receiptInterval);
          return callback(null, receipt);
        }
  
        // return false
        return false;
      });
    }, 100);
  }