removed 1st edition code

17-it-generator/tree/extra/tree.py

@@ -1,13 +0,0 @@
-def tree(cls, level=0, last_in_level=True):
-    yield cls.__name__, level, last_in_level
-    subclasses = cls.__subclasses__()
-    if subclasses:
-    	last = subclasses[-1]
-    for sub_cls in subclasses:
-        yield from tree(sub_cls, level+1, sub_cls is last)
-
-
-if __name__ == '__main__':
-    for cls_name, level, _ in tree(BaseException):
-        indent = ' ' * 4 * level
-        print(f'{indent}{cls_name}')