binary tree level order traversal

 1from binary_tree_node import BinaryTreeNode as N
 2from test_framework import generic_test
 3
 4
 5def lev(t):
 6    result = []
 7    if not t:
 8        return result
 9    s = [t]
10    while s:
11        result.append([x.data for x in s])
12        level_nodes = []
13        for curr in s:
14            if curr.left:
15                level_nodes.append(curr.left)
16            if curr.right:
17                level_nodes.append(curr.right)
18        s = level_nodes
19    return result
20
21
22if __name__ == "__main__":
23    exit(
24        generic_test.generic_test_main(
25            "tree_level_order.py", "tree_level_order.tsv", lev
26        )
27    )