diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index c13aff2a6cd3..4c784f92bc91 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -5096,6 +5096,9 @@ in modules // {
     };
 
     buildInputs = with self; [ pytest ];
+    patchPhase = ''
+      sed -i 's/==2.9.1//' requirements/test.txt
+    '';
 
     meta = with stdenv.lib; {
       description = "Scripting library for tmux";