1 files changed, 1 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 74a7066..19ab53d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -60,6 +60,7 @@ deps =
     pytest
     pytest-mock
     fastnumbers
+    typing_extensions
 commands =
     mypy --strict natsort tests
 skip_install = true