Thank for your answer Chris. I'm a newbie and I just start to learn what is a class and attributes. But when I read your tex I restart the shell and I create a new object and it works. Your message helps me and I think I create the object tab with self surface and then I modified my TableauNoir Class . But I did not know that an object could be old but it sounds very logical when you heard it. Anyway I think your crystal ball works well ...:-)
P.S : sorry for my english. I'm french..... -- https://mail.python.org/mailman/listinfo/python-list