async fn describe_db_cluster_parameter_groups(
        &self,
        input: DescribeDBClusterParameterGroupsMessage,
    ) -> Result<DBClusterParameterGroupsMessage, RusotoError<DescribeDBClusterParameterGroupsError>>
    {
        let mut request = SignedRequest::new("POST", "rds", &self.region, "/");
        let params = self.new_params("DescribeDBClusterParameterGroups");
        let mut params = params;
        DescribeDBClusterParameterGroupsMessageSerializer::serialize(&mut params, "", &input);
        request.set_payload(Some(serde_urlencoded::to_string(&params).unwrap()));
        request.set_content_type("application/x-www-form-urlencoded".to_owned());

        let response = self
            .sign_and_dispatch(
                request,
                DescribeDBClusterParameterGroupsError::from_response,
            )
            .await?;

        let mut response = response;
        let result = xml_util::parse_response(&mut response, |actual_tag_name, stack| {
            xml_util::start_element(actual_tag_name, stack)?;
            let result = DBClusterParameterGroupsMessageDeserializer::deserialize(
                "DescribeDBClusterParameterGroupsResult",
                stack,
            )?;
            skip_tree(stack);
            xml_util::end_element(actual_tag_name, stack)?;
            Ok(result)
        })
        .await?;

        drop(response); // parse non-payload
        Ok(result)
    }
<p> Returns a list of <code>DBClusterParameterGroup</code> descriptions. If a <code>DBClusterParameterGroupName</code> parameter is specified, the list will contain only the description of the specified DB cluster parameter group.</p>
rusoto/services/neptune/src/generated.rs