def delete_repeated(s):
    no_reps = ''
    for letter in s:
        if letter not in no_reps:
            no_reps = no_reps + letter
    return no_reps

# using a list
def delete_repeated_2(s):
    no_reps = []
    for letter in s:
        if letter not in no_reps:
            no_reps.append(letter)
    return ''.join(no_reps)