Fix error display with multiple arguments

basic_display.py

@@ -10,8 +10,8 @@ class BasicDisplay():
         print('|', title, '|')
         print(bar)
 
-    def error(self, message):
-        print('ERROR :', message)
+    def error(self, *message):
+        print('ERROR :', *message)
 
     def product(self, p):
         print(p.id ,':', p.name)