diff --git a/tahoe-lafs.nix b/tahoe-lafs.nix
index eb9a33c10a81cb4dcfebcb282795575089e37bbf..a0b23d65fc410209db3e4f4692f89ce1fc329a97 100644
--- a/tahoe-lafs.nix
+++ b/tahoe-lafs.nix
@@ -4,7 +4,7 @@
 , service-identity, pyyaml, magic-wormhole, treq, appdirs
 , eliot, autobahn, cryptography
 }:
-buildPythonPackage rec {
+python.pkgs.buildPythonPackage rec {
   version = "1.14.0.dev";
   name = "tahoe-lafs-${version}";
   src = fetchFromGitHub {