@Override
    public ValidDBInstanceModificationsMessage describeValidDBInstanceModifications(DescribeValidDBInstanceModificationsRequest request) {
        request = beforeClientExecution(request);
        return executeDescribeValidDBInstanceModifications(request);
    }
<p>
You can call <code>DescribeValidDBInstanceModifications</code> to learn what modifications you can make to your
DB instance. You can use this information when you call <code>ModifyDBInstance</code>.
</p>
<p>
This command doesn't apply to RDS Custom.
</p>

@param describeValidDBInstanceModificationsRequest
@return Result of the DescribeValidDBInstanceModifications operation returned by the service.
@throws DBInstanceNotFoundException
        <code>DBInstanceIdentifier</code> doesn't refer to an existing DB instance.
@throws InvalidDBInstanceStateException
        The DB instance isn't in a valid state.
@sample AmazonRDS.DescribeValidDBInstanceModifications
@see <a href="http://docs.aws.amazon.com/goto/WebAPI/rds-2014-10-31/DescribeValidDBInstanceModifications"
     target="_top">AWS API Documentation</a>
aws-java-sdk-rds/src/main/java/com/amazonaws/services/rds/AmazonRDSClient.java