Source page: http://docs.python.org/3/library/os.html
Entry: os.walk(...)

Ambiguity Source: Name of the argument TopDown and / or its description.

The TopDown name is misleading to me. I would suggest BFS or DFS instead. TopDown false would imply to me that the traversal would run bottom up "from" the directory mentioned in the argument list (even though the name of that argument is top, it is confusing indicating a possibility of another naming mistake instead!)