diff --git a/codes/utils.py b/codes/utils.py
index aa8d3deff3c66137bf1087402702132ce63e33cb..3c9f44da2d8d59358a9a398654e3e2e42d82db1f 100644
--- a/codes/utils.py
+++ b/codes/utils.py
@@ -230,7 +230,7 @@ def build_interacting_syst(builder, lattice, func_onsite, func_hop, max_neighbor
     int_builder : `kwant.Builder`
         Dummy `kwant.Builder` to compute interaction matrix.
     """
-    int_builder = kwant.Builder(kwant.TranslationalSymmetry(**builder.symmetry.periods))
+    int_builder = kwant.Builder(kwant.TranslationalSymmetry(*builder.symmetry.periods))
     int_builder[builder.sites()] = func_onsite
     for neighbors in range(max_neighbor):
         int_builder[lattice.neighbors(neighbors + 1)] = func_hop