diff --git a/proselint/__init__.py b/proselint/__init__.py
index f4c161ada..5483d1f3c 100644
--- a/proselint/__init__.py
+++ b/proselint/__init__.py
@@ -1,4 +1,4 @@
 """Proselint applies advice from great writers to your writing."""
 from . import tools
 
-__all__ = ['tools']
+__all__ = ('tools')