diff --git a/demonstrations/tutorial_QGAN.py b/demonstrations/tutorial_QGAN.py
index 9700c95640..a592242ec8 100644
--- a/demonstrations/tutorial_QGAN.py
+++ b/demonstrations/tutorial_QGAN.py
@@ -213,7 +213,7 @@ def gen_cost(gen_weights):
 cost = lambda: disc_cost(disc_weights)
 
 for step in range(50):
-    opt.minimize(cost, disc_weights)
+    opt.minimize(cost, [disc_weights])
     if step % 5 == 0:
         cost_val = cost().numpy()
         print("Step {}: cost = {}".format(step, cost_val))
@@ -243,7 +243,7 @@ def gen_cost(gen_weights):
 cost = lambda: gen_cost(gen_weights)
 
 for step in range(50):
-    opt.minimize(cost, gen_weights)
+    opt.minimize(cost, [gen_weights])
     if step % 5 == 0:
         cost_val = cost().numpy()
         print("Step {}: cost = {}".format(step, cost_val))