message: remove null which was causing error invoking recordEmissions
diff: @@ -71,8 +71,7 @@ export class EmissionsContractInvoke {
  energyUseAmount,
  energyUseUom,
  url,
  - md5,
  - null
  + md5
  );
  const stringResult: string = blockchainResult.toString("utf-8");
  const jsonResult: any = JSON.parse(stringResult);
  