AttributeError: 'NoneType' object has no attribute 'find_node' (singledist)

[gour]

gour@frugalware:~/repos/Bento$ python tools/singledist.py
Attempt to create singledist script including waf gives:

Creating self-contained script 'bentomaker' in /home/gour/repos/Bento
Traceback (most recent call last):
File "tools/singledist.py", line 206, in
main()
File "tools/singledist.py", line 203, in main
create_script(config)
File "tools/singledist.py", line 140, in create_script
nodes = list_nodes(packages, base_node)
File "tools/singledist.py", line 114, in list_nodes
n = base_node.find_node(init)
AttributeError: 'NoneType' object has no attribute 'find_node'

The python is 2.7.3.

Any idea?