diff --git a/lshash/lshash.py b/lshash/lshash.py
index 5c895a6..750b731 100644
--- a/lshash/lshash.py
+++ b/lshash/lshash.py
@@ -195,7 +195,7 @@ def index(self, input_point, extra_data=None):
         if isinstance(input_point, np.ndarray):
             input_point = input_point.tolist()
 
-        if extra_data:
+        if extra_data is not None:
             value = (tuple(input_point), extra_data)
         else:
             value = tuple(input_point)