temp2351

def missing_letters(user_str):
    """
        This function takes string as argument and prints out the missing letters.
    """
    ht = histogram(user_str)  # Calling the histogram function as a requirement.
    ml = sorted(list(set(alphabet).difference(set(user_str))))
    if not ml:
        return f"{user_str} contains all letters."
    else:
        return f'{"".join(ml)} {"is" if len(ml) == 1 else "are"} missing'


for test in test_dups:
    print(f"In {test}, {missing_letters(test)}")