diff --git a/jupyterhub_authenticator/password.py b/jupyterhub_authenticator/password.py
index 556c7e81e763853e629c4b0faf4430e5a4165977..6581687ad41a24346a06f40f7eada670fa72d668 100644
--- a/jupyterhub_authenticator/password.py
+++ b/jupyterhub_authenticator/password.py
@@ -27,6 +27,6 @@ def checkpw(password, encrypted_password):
 
     try:
         return argon2.PasswordHasher().verify(encrypted_password, password)
-    except argon2.exceptions.InvalidHashError, argon2.exceptions.VerifyMismatchError:
+    except (argon2.exceptions.InvalidHashError, argon2.exceptions.VerifyMismatchError):
         # Rewrite exception to maintain API compatibility.
         return False