diff --git a/networkz/algorithms/approximation/firefighter_problem/Utils.py b/networkz/algorithms/approximation/firefighter_problem/Utils.py
index 97ad797..c62ce68 100644
--- a/networkz/algorithms/approximation/firefighter_problem/Utils.py
+++ b/networkz/algorithms/approximation/firefighter_problem/Utils.py
@@ -521,7 +521,7 @@ def create_st_graph(graph:nx.DiGraph, targets:list, new_target:str) -> nx.DiGrap
     >>> G = nx.DiGraph()
     >>> G.add_edges_from([(1, 2), (2, 3), (3, 4)])
     >>> targets = [2, 3]
-    >>> G_st = create_st_graph(G, targets)
+    >>> G_st = create_st_graph(G, targets, 't')
     >>> 't' in G_st.nodes
     True
     >>> list(G_st.successors(2))
diff --git a/networkz/algorithms/max_flow_with_node_capacity.py b/networkz/algorithms/max_flow_with_node_capacity.py
index c88625e..89997a1 100644
--- a/networkz/algorithms/max_flow_with_node_capacity.py
+++ b/networkz/algorithms/max_flow_with_node_capacity.py
@@ -69,7 +69,7 @@ def min_cut_with_node_capacity(graph: nx.DiGraph, source: int = None, target: in
     >>> G.add_edge(0, 2)
     >>> G.add_edge(2, 3)
     >>> G.add_edge(1, 4)
-    >>> s_t_G = create_st_graph(G, [2,4])
+    >>> s_t_G = create_st_graph(G, [2,4], 't')
     >>> min_cut_nodes = min_cut_with_node_capacity(s_t_G, 0, 4)
     >>> sorted(min_cut_nodes)
     ['2_out', '4_out']