diff --git a/default.nix b/default.nix
index 04193ed1586856a9b21d7403a0cde175071b3344..046aae00876256588381190b25c2a168134a8e4e 100644
--- a/default.nix
+++ b/default.nix
@@ -1,2 +1,2 @@
-{ pkgs ? import ./nixpkgs.nix { }, hypothesisProfile ? null, collectCoverage ? false, testSuite ? null, trialArgs ? [] }:
+{ pkgs ? import ./nixpkgs.nix { }, hypothesisProfile ? null, collectCoverage ? false, testSuite ? null, trialArgs ? null }:
 pkgs.python27Packages.zkapauthorizer.override { inherit hypothesisProfile collectCoverage testSuite trialArgs; }