list, map and put of the Queue in the Tree Data Structure

[DeaD_EyE]

Queue.put returns None, but the method is still called, and the elements are put into the queue.
map can be used to make such funny things. The biggest disadvantage is that you can't do error handling for individual elements.
The second disadvantage is, that the return value of map is not used. In this case, it's useless because there are only Nones.