    # 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