# File lib/fog/aws/requests/rds/describe_db_subnet_groups.rb, line 38
        def describe_db_subnet_groups(name = nil, opts = {})
          response = Excon::Response.new

          subnet_group_set = []
          if name
            if subnet_group = self.data[:subnet_groups][name]
              subnet_group_set << subnet_group
            else
              raise Fog::AWS::RDS::NotFound.new("Subnet Group #{name} not found")
            end
          else
            subnet_group_set = self.data[:subnet_groups].values
          end

          response.status = 200
          response.body = {
            "ResponseMetadata"=>{ "RequestId"=> Fog::AWS::Mock.request_id },
            "DescribeDBSubnetGroupsResult" => { "DBSubnetGroups" => subnet_group_set }
          }
          response
        end