diff --git a/Makefile b/Makefile
index 87cec44..d6242d0 100644
--- a/Makefile
+++ b/Makefile
@@ -55,3 +55,4 @@ clean:
 	find . -type d -name __pycache__ -delete
 	# coverage
 	rm -rf htmlcov .coverage
+	rm -rf .mypy_cache