In each input list, every number repeats at least once, except for two. Write a function that returns the two unique numbers.

retun_unique.py

def retun_unique(lst):
    return [i for i in lst if lst.count(i) <= 1]

return_unique([1, 9, 8, 8, 7, 6, 1, 6]) # -> [9, 7]

return_unique([5, 5, 2, 4, 4, 4, 9, 9, 9, 1]) # -> [2, 1]

return_unique([9, 5, 6, 8, 7, 7, 1, 1, 1, 1, 1, 9, 8]) # -> [5, 6]