How can I find my end devices in my zigbee network with a python script?

Im trying o discover all the devices in my zigbee network through a programable XBee board with a python script. For that I use:

xnet = xbee.get_network()
xnet.start_discovery_process()
while xnet.is_discovery_running():
    time.sleep(0.5)
devices = xnet.get_devices()

the problem is that It only finds the routers and the coordinator but it doesnt find any End device. Is there any way to get ALL the devices in the network?

Thanks