Fixed __str__

Aufgabe03a.py

@@ -6,7 +6,7 @@ class Stack(list):
         max_length = len(str(max(self.stack, key=lambda x: len(str(x)))))
         result = ""
         vert = "\u2502"
-        for ele in self.stack:
+        for ele in reversed(self.stack):
             result += vert + str(ele).rjust(max_length) + vert + "\n"
         return result + "\u2514" + "\u2500"*max_length + "\u2518"