diff --git a/requirements.txt b/requirements.txt
index ac12242..165665d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 Pygments>=2.4
+typing-extensions>=4.12.0
 sphinx
 sphinxcontrib-spelling
 sphinx-rtd-theme>=0.5.2