list sort() function bring backs None

[CompleteNewb]

i have a program that gives back a random list of numbers which i then sort using .sort() , but then this happened:

    list1 = [1,1,1,1,1]
    list2 = list1.sort[]
    print(list2)

output

None

why doesn't it just return

[1,1,1,1,1]

and what kind i do to bypass that problem?