def reserved_db_instances(options = {})
      batches = Enumerator.new do |y|
        resp = @client.describe_reserved_db_instances(options)
        resp.each_page do |page|
          batch = []
          page.data.reserved_db_instances.each do |r|
            batch << ReservedDBInstance.new(
              id: r.reserved_db_instance_id,
              data: r,
              client: @client
            )
          end
          y.yield(batch)
        end
      end
      ReservedDBInstance::Collection.new(batches)
    end
def reserved_db_instances(options = {})
      batches = Enumerator.new do |y|
        resp = @client.describe_reserved_db_instances(options)
        resp.each_page do |page|
          batch = []
          page.data.reserved_db_instances.each do |r|
            batch << ReservedDBInstance.new(
              id: r.reserved_db_instance_id,
              data: r,
              client: @client
            )
          end
          y.yield(batch)
        end
      end
      ReservedDBInstance::Collection.new(batches)
    end
@example Request syntax with placeholder values

   reserved_db_instances = rds.reserved_db_instances({
     reserved_db_instance_id: "String",
     reserved_db_instances_offering_id: "String",
     db_instance_class: "String",
     duration: "String",
     product_description: "String",
     offering_type: "String",
     multi_az: false,
     filters: [
       {
         name: "String", # required
         values: ["String"], # required
       },
     ],
   })
 @param [Hash] options ({})
 @option options [String] :reserved_db_instance_id
   The reserved DB instance identifier filter value. Specify this
   parameter to show only the reservation that matches the specified
   reservation ID.
 @option options [String] :reserved_db_instances_offering_id
   The offering identifier filter value. Specify this parameter to show
   only purchased reservations matching the specified offering
   identifier.
 @option options [String] :db_instance_class
   The DB instance class filter value. Specify this parameter to show
   only those reservations matching the specified DB instances class.
 @option options [String] :duration
   The duration filter value, specified in years or seconds. Specify this
   parameter to show only reservations for this duration.

   Valid Values: `1 | 3 | 31536000 | 94608000`
 @option options [String] :product_description
   The product description filter value. Specify this parameter to show
   only those reservations matching the specified product description.
 @option options [String] :offering_type
   The offering type filter value. Specify this parameter to show only
   the available offerings matching the specified offering type.

   Valid Values: `"Partial Upfront" | "All Upfront" | "No Upfront" `
 @option options [Boolean] :multi_az
   The Multi-AZ filter value. Specify this parameter to show only those
   reservations matching the specified Multi-AZ parameter.
 @option options [Array<Types::Filter>] :filters
   This parameter is not currently supported.
 @return [ReservedDBInstance::Collection]