light only works with loop

[djs4000]

Hello,
I am both new to python, DMX and serial communication, so i hope you will bear with me.
I am trying to control a simple LED parcan light, it has 4 channels (1 master dimmer and 3 for RGB). This is the first library that has actually worked with my USB to DMX cable so thank you for writing this script. After some testing, I found that the light stays on only while I am sending a signal.
so
dmx.set_data(1,255) doesn't work, but
while True: dmx.set_data(1,255)
Does work.
Is this intended? is it perhaps an issue with the light I have? As a total newb i would forever be in your debt if you were to point me in the right direction.