Could we have a prod_id_to_channels that we populate here? then a
conflict_prods = [x for (x,y) in prod_id_to_channels.items() if len(y) > 1]
for p_id in conflict_prods:
    print "product %s has multile certs: % p_id
    for cert in applicable_certs[p_id]:
         for channel in applicable_certs[p_id][cert]:
              print channel

meh, maybe not any better