diff --git a/cyaron/graph.py b/cyaron/graph.py
index 66ae82d..48e8f0a 100644
--- a/cyaron/graph.py
+++ b/cyaron/graph.py
@@ -79,10 +79,9 @@ def to_str(self, **kwargs):
             **kwargs(Keyword args):
                 bool shuffle = False -> whether shuffle the output or not
                 str output(Edge) = str -> the convert function which converts object Edge to str. the default way is to use str()
-                list[int] node_shuffler(list[int])
-                = lambda table: random.sample(table, k=len(table))
+                list[int] node_shuffler(int)
+                = lambda n: random.sample(range(1, n + 1), k=n)
                 -> the random function which shuffles the vertex sequence.
-                    Note that this function will actually be passed in a `range`!
                 list[Edge] edge_shuffler(list[Edge])
                 -> a random function. the default is to shuffle the edge sequence,
                     also, if the graph is undirected, it will swap `u` and `v` randomly.
@@ -96,10 +95,10 @@ def _edge_shuffler_default(table):
 
         shuffle = kwargs.get("shuffle", False)
         output = kwargs.get("output", str)
-        node_shuffler = kwargs.get("node_shuffler", lambda table: random.sample(table, k=len(table)))
+        node_shuffler = kwargs.get("node_shuffler", lambda n: random.sample(range(1, n + 1), k=n))
         edge_shuffler = kwargs.get("edge_shuffler", _edge_shuffler_default)
         if shuffle:
-            new_node_id = [0] + node_shuffler(range(1, len(self.edges)))
+            new_node_id = [0] + node_shuffler(self.vertex_count())
             edge_buf = []
             for edge in self.iterate_edges():
                 edge_buf.append(
diff --git a/cyaron/tests/graph_test.py b/cyaron/tests/graph_test.py
index f42959e..9a2d6e6 100644
--- a/cyaron/tests/graph_test.py
+++ b/cyaron/tests/graph_test.py
@@ -221,9 +221,8 @@ def unit_test(n, m, shuffle_kwargs = {}, check_kwargs = {}):
         unit_test(8, 20)
         unit_test(8, 20, {"shuffle": True})
         mapping = [0] + random.sample(range(1, 8), k = 7)
-        shuffer = lambda seq: list(map(lambda i: mapping[i], seq))
+        shuffer = lambda n: list(map(lambda i: mapping[i], range(1, n + 1)))
         unit_test(7, 10, {"shuffle": True, "node_shuffler": shuffer})
         unit_test(7, 14, {"shuffle": True, "node_shuffler": shuffer}, {"mapping": mapping})
         shuffer_without_swap = lambda table: random.sample(table, k=len(table))
         unit_test(7, 12, {"shuffle": True, "edge_shuffler": shuffer_without_swap}, {"directed": True})
-