A utility method for cleaning up expired sessions that IIS failed to delete. The method performs a scan on the table
            with a condition that the expiration date is in the past and calls delete on all the keys returned. Scans can be costly on performance
            so use this method sparingly like a nightly or weekly clean job.
            
 Declaration Syntax
 Declaration Syntax| C# | 
public static void DeleteExpiredSessions( AmazonDynamoDB dbClient, string tableName )
 Parameters
 Parameters- dbClient (AmazonDynamoDB)
- The AmazonDynamoDB client used to find a delete expired sessions.
- tableName (String)
- The table to search.