diff --git a/plesna/graph/graph.py b/plesna/graph/graph.py
index 2764bb2..ca09e82 100644
--- a/plesna/graph/graph.py
+++ b/plesna/graph/graph.py
@@ -1,5 +1,4 @@
 from functools import reduce
-from typing import Callable
 
 from pydantic import BaseModel
 
diff --git a/plesna/graph/graph_set.py b/plesna/graph/graph_set.py
index a52fdfc..e03d654 100644
--- a/plesna/graph/graph_set.py
+++ b/plesna/graph/graph_set.py
@@ -12,10 +12,9 @@ class Node(BaseModel):
 
 
 class EdgeOnSet(BaseModel):
-    arrow: Callable
-    sources: dict[str, Node]
-    targets: dict[str, Node]
-    edge_kwrds: dict = {}
+    arrow: str
+    sources: list[Node]
+    targets: list[Node]
 
 
 class GraphSet:
@@ -25,8 +24,8 @@ class GraphSet:
 
     def append(self, edge: EdgeOnSet):
         self._edges.append(edge)
-        self._node_sets.add(frozenset(edge.sources.values()))
-        self._node_sets.add(frozenset(edge.targets.values()))
+        self._node_sets.add(frozenset(edge.sources))
+        self._node_sets.add(frozenset(edge.targets))
 
     @property
     def node_sets(self):
diff --git a/tests/graphs/test_graph_set.py b/tests/graphs/test_graph_set.py
index c402202..1806f7e 100644
--- a/tests/graphs/test_graph_set.py
+++ b/tests/graphs/test_graph_set.py
@@ -2,17 +2,13 @@ from plesna.graph.graph_set import EdgeOnSet, GraphSet, Node
 
 
 def test_init():
+    graph_set = GraphSet()
+
     nodeA = Node(name="A")
     nodeB = Node(name="B")
     nodeC = Node(name="C")
+    edge1 = EdgeOnSet(arrow="arrow", sources=[nodeA, nodeB], targets=[nodeC])
 
-    def arrow(sources, targets):
-        targets["C"].infos["res"] = sources["A"].name + sources["B"].name
-
-    edge1 = EdgeOnSet(
-        arrow=arrow, sources={"A": nodeA, "B": nodeB}, targets={"C": nodeC}
-    )
-    graph_set = GraphSet()
     graph_set.append(edge1)
 
     assert graph_set.node_sets == {frozenset([nodeA, nodeB]), frozenset([nodeC])}