discover_bulb() doesn't work

Hey

I tried to discover my two bulbs (v 1.4.1_48) but the function discover_bulbs() returns an empty list.

I tried this on my win7 and linux machines with python 2 and 3; nothing works.

I also tried to check if the command is realy send and I can receive the correct message:

M-SEARCH * HTTP/1.1
ST:wifi_bulb
MAN:"ssdp:discover"

Can anybody help me?

thx yugon