code: function getDynamoDBEventSourceTableName(record) {
    return record && record.eventSourceARN ? arns.getArnResources(record.eventSourceARN).resource : '';
  }
docs: Extracts and returns the table name from the given DynamoDB stream event record's eventSourceARN (if any); otherwise
  returns an empty string.
  @param {DynamoDBEventRecord|*} record - a DynamoDB stream event record
  @returns {string} the table name (if any) or an empty string (if none)