diff --git a/scripts/cluster_network.py b/scripts/cluster_network.py
index 0124017e..9e55581f 100644
--- a/scripts/cluster_network.py
+++ b/scripts/cluster_network.py
@@ -79,7 +79,7 @@ def distribute_clusters(n, n_clusters, solver_name=None):
         return (1, N[n_id])
     m.n = po.Var(list(L.index), bounds=n_bounds, domain=po.Integers)
     m.tot = po.Constraint(expr=(po.summation(m.n) == n_clusters))
-    m.objective = po.Objective(expr=po.sum((m.n[i] - L.loc[i]*n_clusters)**2
+    m.objective = po.Objective(expr=po.summation((m.n[i] - L.loc[i]*n_clusters)**2
                                            for i in L.index),
                                sense=po.minimize)