'Start up switches in per-server batches'

@classmethod
def batchStartup(cls, switches, **_kwargs):

    key = attrgetter('server')
    for (server, switchGroup) in groupby(sorted(switches, key=key), key):
        info(('(%s)' % server))
        group = tuple(switchGroup)
        switch = group[0]
        OVSSwitch.batchStartup(group, run=switch.cmd)
    return switches
