Python 运行回文查找器代码时发生错误：[类型错误：builtin_index_or_system对象不可订阅]

回文|帕帕尔·恩·德罗姆| noun 向后读与向前读相同的单词、短语或序列，例如，女士或护士跑.

"palindrome_finder"项目包括3个文件:名为"dict.yx"的词典文件、名为"feed_dictionary. py"的词典加载器文件，以及名为"palingram_finder. py"的主文件(识别词典文件中的palindrome).

一旦我运行该文件，我就会收到以下错误:

Traceback (most recent call last):
  File "/Users/cheshirecat/Desktop/python_projects/palingram_finder/palingram_finder.py", line 16, in <module>
    if word[::-1] == word and len(word) >= 3:
       ~~~~^^^^^^
TypeError: 'builtin_function_or_method' object is not subscriptable
[Finished in 58ms with exit code 1]

对于上下文，这里是两个pony文件.

100

import sys

def load(file):
    """Open a text file and return a list of lowercase strings"""

    try:
        with open(file) as in_file:
            loaded_txt = in_file.read().strip().split()
            loaded_txt = [x.lower for x in loaded_txt]

            return loaded_txt

    except IOError as e:
        print("{}\n Error opening {}. Terminating program.".format(e, file), file=sys.stderr)
        sys.exit(1)

100

from load_dictionary import load
from pprint import pp

word_list = load('./dict.txt')
palindrome_list = []

for word in word_list:
    if word[::-1] == word and len(word) >= 3:
        palindrom_list.append(word)

print("Number of palindromes found: {}\n\n".format(len(palindrome_list)))
pp(palindrome_list)

Attempts at a fix: 我使用内置的Python shell测试了回文识别代码的简化版本，如下所示.

>>> word_list = ['betrayal', 'enigma', 'tenet', 'multitude', 'did']
>>> 
>>> palindrome_list = []
>>> 
>>> for word in word_list:
...     if len(word) >= 3 and word[::-1] == word:
...             palindrome_list.append(word)
... 
>>> palindrome_list
['tenet', 'did']
>>> exit()

由于它有效，我认为问题出在加载字典的方式上. 这就是我陷入困境的地方，因为当我以与load_dictionary.py相同的方式在Sublime text editor's shell中加载字典时，我会得到一个字符串列表.那么它不应该起作用吗？