diff --git a/src/oemof/network/network/nodes.py b/src/oemof/network/network/nodes.py
index 8cbc983..0a4b6c9 100644
--- a/src/oemof/network/network/nodes.py
+++ b/src/oemof/network/network/nodes.py
@@ -34,7 +34,7 @@ class Node(Entity):
     ----------
     inputs: dict
         A dictionary mapping input nodes to corresponding inflows.
-    outputs: list or dict, optional
+    outputs: dict
         A dictionary mapping output nodes to corresponding outflows.
     """