diff --git a/hummuspy/src/hummuspy/create_multilayer.py b/hummuspy/src/hummuspy/create_multilayer.py
index 13500cf..c3b7443 100644
--- a/hummuspy/src/hummuspy/create_multilayer.py
+++ b/hummuspy/src/hummuspy/create_multilayer.py
@@ -8,6 +8,7 @@
 import os
 import pandas
 import sys
+import copy
 
 from joblib import delayed, Parallel, dump, load
 
@@ -913,4 +914,4 @@ def __parse_seed(self):
 
         seed_obj = Seed(path='', multiplexall=self.multiplexall_obj, seeds = self.seeds)
 
-        return seed_obj
\ No newline at end of file
+        return seed_obj