我是Python新手。當(dāng)我運(yùn)行以下代碼時出現(xiàn)此錯誤---------------------------------------------------------------------------TypeError                                 Traceback (most recent call last)<ipython-input-17-cdb5a334e110> in <module>     16      17 duplicates_removed = clean_strings---> 18 duplicates_removed = list(dict.fromkeys(duplicates_removed))     19 print(duplicates_removed)TypeError: 'function' object is not iterable有人可以指出我正確的方向嗎？代碼import redef remove_punctuation(value):    return re.sub('[!#?]', '', value)clean_ops = [str.strip, remove_punctuation, str.title]def clean_strings(strings, ops):    result = []    for value in strings:        for function in ops:            value = function(value)        result.append(value)    return resultclean_strings(states_1, clean_ops)duplicates_removed = clean_stringsduplicates_removed = list(dict.fromkeys(duplicates_removed))print(duplicates_removed)