code: function validateDynamoDBStreamEventRecord(record) {
    _validateStreamEventRecord(record);
  
    if (record.eventSource !== "aws:dynamodb") {
      throw new Error(`Unexpected eventSource (${record.eventSource}) on DynamoDB stream event record (${record.eventID})`)
    }
    _validateDynamoDBStreamEventRecord(record);
  }
docs: Validates the given DynamoDB stream event record and raises an error if the record fails to meet any of the following criteria:
  1. It must be a valid stream event record according to {@linkcode _validateStreamEventRecord};
  2. It must be a DynamoDB stream event record (i.e. must contain an eventSource of "aws:dynamodb");
  3. It must contain dynamodb, dynamodb.Keys and dynamodb.StreamViewType properties; and
  4. It should contain dynamodb.NewImage and/or dynamodb.OldImage properties according to its StreamViewType.
  
  @param {DynamoDBEventRecord|*} record - a DynamoDB stream event record
  @throws {Error} if the record is invalid