pbulk: "Unresolvable dependency" is unclear

[Mayuresh <mayuresh%acm.org@localhost>]

bulkbuild reports

    Resolving...
    Unresolvable dependencies found, exiting:
    lang/py-six

There are multiple packages in the bulk build that declare py-six
dependency. Checked the version they declare. It is less than the one
available in lang/py-six.

So not sure why it complains.

In bulklog there is only meta and the files do not give any exact clue
about the unmet dependency.

What is pbulk trying to tell here?

-- 
Mayuresh