Convert milliseconds to hours, min, and seconds python

I need to convert milliseconds to seconds minute hours. I have code like

def convertMillis(millis):
    seconds=(milli/1000)%60
    minutes=(milli/(1000*60))%60
    hours=(milli/(1000*60*60))%24

    return

def main():
    milli=print(input("Enter time in milliseconds "))

    print(hours,":",minutes,":",seconds

main()

But it's not a very good solution.

I would like to know the most pythonic way to do something like

>>> convertmillis(5500)
0:0:5