diff --git a/src/lib.rs b/src/lib.rs
index 3057ef0..99a6017 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -152,7 +152,7 @@ impl<'a> Display for TrustedTypes<'a> {
 }
 
 pub fn csp_middleware<'a, State: 'static + Clone + Send + Sync>(
-    directives: &'a [Directive],
+    directives: &'a [Directive<'a>],
 ) -> impl Fn(Request<State>, Next<'a, State>) -> Pin<Box<dyn Future<Output = tide::Result> + Send + 'a>>
 {
     move |req: Request<State>, next: Next<'a, State>| {