diff --git a/docs/hazmat/primitives/key-derivation-functions.rst b/docs/hazmat/primitives/key-derivation-functions.rst
index a91d8ca..1937c2e 100644
--- a/docs/hazmat/primitives/key-derivation-functions.rst
+++ b/docs/hazmat/primitives/key-derivation-functions.rst
@@ -145,7 +145,7 @@
         ...     info=info,
         ...     backend=backend
         ... )
-        >>> key = hkdf.derive(b"input key)
+        >>> key = hkdf.derive(b"input key")
         >>> hkdf = HKDF(
         ...     algorithm=hashes.SHA256(),
         ...     length=32,