diff --git a/src/proxy.rs b/src/proxy.rs
index 915ef7c95..53d5b6b54 100644
--- a/src/proxy.rs
+++ b/src/proxy.rs
@@ -255,6 +255,7 @@ impl Proxy {
     /// # Ok(())
     /// # }
     /// # fn main() {}
+    /// ```
     pub fn custom<F, U: IntoProxyScheme>(fun: F) -> Proxy
     where
         F: Fn(&Url) -> Option<U> + Send + Sync + 'static,