'Format an external-command notification string.
cmd - Nagios command ID.
host - Host to en/disable notifications on.. A value is not required
for global downtime
svc - Service to schedule downtime for. A value is not required
for host downtime.
Syntax: [submitted] COMMAND;<host_name>[;<service_description>]'

def _fmt_notif_str(self, cmd, host=None, svc=None):

    entry_time = self._now()
    notif_str = ('[%s]    %s' % (entry_time, cmd))
    if (host is not None):
        notif_str += (';%s' % host)
        if (svc is not None):
            notif_str += (';%s' % svc)
    notif_str += '\n'
    return notif_str
