# Print duplicate characters in a string


def get_dup_chars(input_str):
    dedupe_str = ""
    dup_chars = []

    for char in input_str:
        if char not in dedupe_str:
            dedupe_str += char
        else:
            dup_chars.append(char)

    return dup_chars


result = get_dup_chars("zmaxxazkgv")
print(result)  # ['x', 'a', 'z']
