除了合并new_title语句之外，我如何使用Python3重构此代码？请帮助:(

Question

small_words = ('into', 'the', 'a', 'of', 'at', 'in', 'for', 'on') 
def book_title(title): 
    """ Takes a string and returns a title-case string. 
    All words EXCEPT for small words are made title case 
    unless the string starts with a preposition, in which 
    case the word is correctly capitalized. 

    >>> book_title('DIVE Into python') 
    'Dive into Python' 

    >>> book_title('the great gatsby') 
    'The Great Gatsby' 

    >>> book_title('the WORKS OF AleXANDer dumas') 
    'The Works of Alexander Dumas' 
    """ 
    lst_of_words = title.lower().split() 
    num_of_words = len(lst_of_words) 
    if num_of_words < 1: 
     return '' 
    new_title = lst_of_words.pop(0) 
    new_title = new_title[0].upper() + new_title[1:] 
    tpl_of_words = tuple(lst_of_words) 
    for word in tpl_of_words: 
     prep_word = False 
     for prep in small_words: 
      if prep == word: 
       new_title = new_title + ' ' + word 
       new_title = new_title + word 
       prep_word = True 
       break 
     if prep_word == True: 
      continue 
     new_title = new_title + ' '+ word[0].upper()+ word[1:] 
     new_title = new_title + word[0].upper() 
     new_title = new_title + word[1:] 
    return new_title 

def _test(): 
    import doctest, refactory 
    return doctest.testmod(refactory) 

if __name__ == "__main__": 
    _test() 

Answer 1

return ' '.join((new[0].upper() + new[1:]) if (ix == 0 or new not in small_words) 
    else new for (ix, new) in enumerate(title.lower().split()))