Code review comment for lp:~rvb/launchpad/bug-869221

19 + if (len(potential_nominated_arches) == 0):
20 + raise InitializationError(
21 + ("The distroseries has no architectures selected to "
22 + "build architecture independent binaries."))

Nit - too many parentheses here, on all four lines :)

Everything else looks great, thanks!