Write a Python function that takes a list and returns a new list with unique elements of the first list

 def unique_list(l):

    x = []

    for a in l:

        if a  not in x:

            x.append(a)

    return x

print (unique_list([1,2,3,4,1,2,3,5,6,8,1,2,3]))

#OUTPUT

#[1, 2, 3, 4, 5, 6, 8]