diff --git a/haystack/nodes/other/shaper.py b/haystack/nodes/other/shaper.py
index 26ae6162bd..a229234c69 100644
--- a/haystack/nodes/other/shaper.py
+++ b/haystack/nodes/other/shaper.py
@@ -740,7 +740,7 @@ def run(  # type: ignore
         if labels and "labels" not in invocation_context.keys():
             invocation_context["labels"] = labels
 
-        if documents and "documents" not in invocation_context.keys():
+        if documents != None and "documents" not in invocation_context.keys():
             invocation_context["documents"] = documents
 
         if meta and "meta" not in invocation_context.keys():