diff --git a/physutils/physio.py b/physutils/physio.py
index 8c9ce8f..f557001 100644
--- a/physutils/physio.py
+++ b/physutils/physio.py
@@ -372,7 +372,7 @@ def fs(self):
 
     @property
     def history(self):
-        """Functions that have been performed on / modified `data`"""
+        """Functions that have been performed on / modified `data`."""
         return self._history
 
     @property