Por alguns dias, as compilações de ReadTheDocs estão falhando e não sei por quê.

Os erros não fazem sentido para mim. Eles não me dizem qual dos documentos é ruim nem por quê.

As coisas que mudaram nas últimas semanas foram que estou usando meu editor de markdown de uma forma que se integra diretamente ao GitHub. E tenho adicionado iframes de receita repl.it ao livro de receitas. Eu não acho que o readme tenha nenhum ainda.

Não acho que sejam os iframes porque eles estão funcionando no livro de receitas de trabalho atual localizado aqui
http://cookbook.PySimpleGUI.org

Leia-me aqui:
http://www.PySimpleGUI.org

Qualquer ajuda seria muito apreciada!!!

Aqui está um exemplo de construção:
https://readthedocs.org/projects/pysimplegui/builds/8589243/

Build #8589243
latest (1eb3c26878e321867fb1dc28d94353d2087fed3f)
Build failed
git clone --no-single-branch --depth 50 https://github.com/PySimpleGUI/PySimpleGUI .
git checkout --force origin/master
git clean -d -f -f
python3.7 -mvirtualenv --no-site-packages --no-download /home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest
/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/bin/python -m pip install --upgrade --cache-dir /home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/.cache/pip pip
/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/bin/python -m pip install --upgrade --cache-dir /home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/.cache/pip Pygments==2.2.0 setuptools<40 docutils==0.13.1 mock==1.0.1 pillow==2.6.1 alabaster>=0.7,<0.8,!=0.7.5 commonmark==0.5.4 recommonmark==0.4.0 mkdocs==0.17.3
cat mkdocs.yml
python /home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/bin/mkdocs build --clean --site-dir _build/html --config-file /home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/checkouts/latest/mkdocs.yml
INFO    -  Cleaning site directory 
INFO    -  Building documentation to directory: /home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/checkouts/latest/_build/html 
Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/mkdocs/nav.py", line 337, in _follow
    raise StopIteration
StopIteration

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/bin/mkdocs", line 10, in <module>
    sys.exit(cli())
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/mkdocs/__main__.py", line 156, in build_command
    ), dirty=not clean)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/mkdocs/commands/build.py", line 282, in build
    build_pages(config, dirty=dirty)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/mkdocs/commands/build.py", line 213, in build_pages
    site_navigation = nav.SiteNavigation(config)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/mkdocs/nav.py", line 44, in __init__
    config, self.url_context)
  File "/home/docs/checkouts/readthedocs.org/user_builds/pysimplegui/envs/latest/lib/python3.7/site-packages/mkdocs/nav.py", line 392, in _generate_site_navigation
    config_line, url_context, config):
RuntimeError: generator raised StopIteration