Error
Traceback (most recent call last):
  File "...\Python36\lib\unittest\case.py", line 59, in testPartExecutor
    yield
  File "...\Python36\lib\unittest\case.py", line 605, in run
    testMethod()
  File "...\pywikibot-core\tests\proofreadpage_tests.py", line 686, in test_page_gen_redlink
    self.assertEqual(list(gen), self.pages)
  File "...\pywikibot-core\pywikibot\proofreadpage.py", line 887, in <genexpr>
    gen = (p for p in gen if p.ql in filter_ql)
  File "...\pywikibot-core\pywikibot\proofreadpage.py", line 281, in wrapper
    obj._decompose_page()
  File "...\pywikibot-core\pywikibot\proofreadpage.py", line 444, in _decompose_page
    if not (hasattr(self, '_text') or self.text):
  File "...\pywikibot-core\pywikibot\proofreadpage.py", line 408, in text
    self._text = self.preloadText()
  File "...\pywikibot-core\pywikibot\page.py", line 665, in preloadText
    self.site.loadpageinfo(self, preload=True)
  File "...\pywikibot-core\pywikibot\site.py", line 2967, in loadpageinfo
    self._update_page(page, query)
  File "...\pywikibot-core\pywikibot\site.py", line 2950, in _update_page
    for pageitem in query:
  File "...\pywikibot-core\pywikibot\data\api.py", line 2775, in __iter__
    self.data = self.request.submit()
  File "...\pywikibot-core\pywikibot\data\api.py", line 2128, in submit
    raise e
pywikibot.data.api.APIMWException: internal_api_error_BadMethodCallException: [Wh@7dApAEMUAAKjKXTkAAACD] Exception caught: Call to a member function exists() on a non-object (boolean) [servedby:mw1316]