def restore_db_instance_from_db_snapshot(snapshot_aws_id, instance_aws_id, params={})
request_hash = { 'DBSnapshotIdentifier' => snapshot_aws_id,
'DBInstanceIdentifier' => instance_aws_id }
request_hash['DBInstanceClass'] = params[:instance_class] unless params[:instance_class].blank?
request_hash['EndpointPort'] = params[:endpoint_port] unless params[:endpoint_port].blank?
request_hash['AvailabilityZone'] = params[:availability_zone] unless params[:availability_zone].blank?
link = generate_request('RestoreDBInstanceFromDBSnapshot', request_hash)
request_info(link, DescribeDbInstancesParser.new(:logger => @logger))[:db_instances].first
end