    # File lib/fog/aws/requests/rds/describe_db_engine_versions.rb, line 8
            def describe_db_engine_versions(opts={})
              params = {}
              params['DBParameterGroupFamily'] = opts[:db_parameter_group_family] if opts[:db_parameter_group_family]
              params['DefaultOnly'] = opts[:default_only] if opts[:default_only]
              params['Engine'] = opts[:engine] if opts[:engine]
              params['EngineVersion'] = opts[:engine_version] if opts[:engine_version]
              params['Marker'] = opts[:marker] if opts[:marker]
              params['MaxRecords'] = opts[:max_records] if opts[:max_records]

              request({
                'Action'  => 'DescribeDBEngineVersions',
                :parser   => Fog::Parsers::AWS::RDS::DescribeDBEngineVersions.new
              }.merge(params))
            end