def duplicates_remove(txt: str) -> str:
    seen = ""
    result = ""
    for char in txt:
        if char not in seen:
            result += char
            seen += char
    return result

def main_7ex():
    txt1 = "banana"
    print(f'{txt1} {duplicates_remove(txt1)}')

    txt2 = "apple"
    print(f'{txt2} {duplicates_remove(txt2)}')

    txt3 = "pear"
    print(f'{txt3} {duplicates_remove(txt3)}')

main_7ex()