我试图使用connexion运行一个简单的python代码，该代码在本地Pycharm上运行良好，但是在推动云铸造时却出现了错误；依赖关系通过供应商文件夹提供。虽然我还添加了flake8 3.7.7依赖关系，但仍然面临相同的错误。有指针吗？
Complete output from command python setup.py egg_info:
Download error on https://pypi.org/simple/flake8/: [Errno -2] Name or service not known -- Some packages may not be found!
Couldn't find index page for 'flake8' (maybe misspelled?)
Download error on https://pypi.org/simple/: [Errno -2] Name or service not known -- Some packages may not be found!
No local packages or working download links found for flake8
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/tmp/pip-build-CwV8c_/connexion/setup.py", line 132, in <module>
entry_points={'console_scripts': ['connexion = connexion.cli:main']}
File "build/bdist.linux-x86_64/egg/setuptools/__init__.py", line 139, in setup
File "build/bdist.linux-x86_64/egg/setuptools/__init__.py", line 134, in _install_setup_requires