code: function getEventAwsRegions(event) {
    return event && event.Records ?
      event.Records.map(record => record.awsRegion ? trimOrEmpty(event.awsRegion) : '') : [];
  }
docs: Extracts the regions from the given event's record's awsRegion properties (if any); otherwise returns an empty array.
  
  Note that for this to work rhe given event should have records with an awsRegion property, which is the case for AWS
  Kinesis and DynamoDB stream events and for S3 Put and Delete events (and possibly for other AWS events as well).
  
  @param event the event from which to extract its records' AWS regions
  @returns {string[]} the event's records' AWS regions (if any) or an empty array