'Kill running pids
:param graceful: if True, attempt SIGHUP on supporting servers
:returns: a dict mapping pids (ints) to pid_files (paths)'

def kill_running_pids(self, **kwargs):

    graceful = kwargs.get('graceful')
    if (graceful and (self.server in GRACEFUL_SHUTDOWN_SERVERS)):
        sig = signal.SIGHUP
    else:
        sig = signal.SIGTERM
    return self.signal_pids(sig, **kwargs)
