diff --git a/datawrapper/__main__.py b/datawrapper/__main__.py
index a209076..e969d36 100644
--- a/datawrapper/__main__.py
+++ b/datawrapper/__main__.py
@@ -809,7 +809,7 @@ def update_chart(
             obj = self.get_chart(chart_id)
 
         # Add data, if provided
-        if data:
+        if data is not None:
             self.add_data(chart_id=obj["id"], data=data)
 
         # Return the result