diff --git a/crates/ptth_relay/src/scraper_api.rs b/crates/ptth_relay/src/scraper_api.rs
index d74c8bf..3165ec3 100644
--- a/crates/ptth_relay/src/scraper_api.rs
+++ b/crates/ptth_relay/src/scraper_api.rs
@@ -231,7 +231,7 @@ async fn metrics (
 {
 	let mut s = String::with_capacity (4 * 1_024);
 	
-	let mut push_metric = |name, help, kind, value| {
+	let mut push_metric = |name, help: Option<&str>, kind, value| {
 		if let Some (help) = help {
 			s.push_str (format! ("# HELP {} {}\n", name, help).as_str ());
 		}