# File lib/fog/aws/requests/rds/describe_orderable_db_instance_options.rb, line 39
        def describe_orderable_db_instance_options(engine=nil, opts={})
          instance_options = []
          response = Excon::Response.new
          if engine
            (opts[:db_instance_class] || %w(db.m2.xlarge db.m1.large)).each do |size|
              instance_options << {'MultiAZCapable' => true,
                                   'Engine' => engine,
                                   'LicenseModel' => opts[:license_model] || 'general-public-license',
                                   'ReadReplicaCapable' => true,
                                   'EngineVersion' => opts[:engine_version] || '5.6.12',
                                   'AvailabilityZones' => [
                                      {'Name' => 'us-east-1b', 'ProvisionedIopsCapable' => true},
                                      {'Name' => 'us-east-1c', 'ProvisionedIopsCapable' => true},
                                      {'Name' => 'us-east-1d', 'ProvisionedIopsCapable' => false},
                                      {'Name' => 'us-east-1e', 'ProvisionedIopsCapable' => true}],
                                   'DBInstanceClass' => size,
                                   'Vpc' => opts[:vpc].nil? ? true : opts[:vpc]}

            end
          else
            raise Fog::AWS::RDS::NotFound.new('An engine must be specified to retrieve orderable instance options')
          end

          response.status = 200
          response.body = {
              'ResponseMetadata' => { 'RequestId' => Fog::AWS::Mock.request_id },
              'DescribeOrderableDBInstanceOptionsResult' => { 'OrderableDBInstanceOptions' => instance_options }
          }
          response
        end