diff --git a/idtxl/idtxl_io.py b/idtxl/idtxl_io.py
index 338ddc0a..65c20f35 100644
--- a/idtxl/idtxl_io.py
+++ b/idtxl/idtxl_io.py
@@ -6,6 +6,7 @@
 # import json
 import pickle
 import h5py
+import networkx as nx
 import numpy as np
 import copy as cp
 import itertools as it