How can I write a list without duplicate with only for, if and boolean

Question

My professor gave me an exercise where I write a function that returns a list without the duplicate to the old list. This is the code but I don\'t know how to write the meth

Answer 1

def distinct(lst):
    dlst = []
    for val in lst:
        if val not in dlst:
            dlst.append(val)
    return dlst