diff --git a/tools.py b/tools.py
index ab4454adecd0d14dc905c4c3ce0d3a25dd04f41d..9de66fa5d45d84b71843e2bb090dace4b51a73bb 100644
--- a/tools.py
+++ b/tools.py
@@ -283,7 +283,7 @@ class Memory:
         try:
             max_value = self.memory[self.max_idx]
         except IndexError:
-            max_value = [[-1, -1, -1]]
+            max_value = np.array([[-1, -1, -1]])
 
         return max_value