请教一个问题。

最近开始学 python ，以前没怎么接触编程，就大二的时候有学过 vb 。
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def number_generator():
n = 11
while True:
yield n
n = n + 1


def palindrome_check(n):
string = str(n)
return string[0] == string[::-1]


def next_number():
it = number_generator()
while True:
n = next(it)
yield n
it = filter(palindrome_check(n), it)


for a in next_number():
if a < 1000:
print(a)
else:
break
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这是判断回数的代码，但是一直出错
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Traceback (most recent call last):
File "C:/Users/Administrator/AppData/Local/Programs/Python/Python35-32/HH.py", line 21, in <module>
for a in huishu():
File "C:/Users/Administrator/AppData/Local/Programs/Python/Python35-32/HH.py", line 16, in huishu
n = next(it)
TypeError: 'bool' object is not callable
----------------------------------------------------------------------------------------------------------------------------------------------请问问题在哪啊（为什么没排版？？？？？？）