```lang=python
Collecting backport-collections; python_version in "2.4, 2.5, 2.6" (from vcrpy->vcrpy-unittest->-r dev-requirements.txt (line 27))
Downloading backport_collections-0.1.tar.gz
Collecting PyYAML (from vcrpy->vcrpy-unittest->-r dev-requirements.txt (line 27))
Downloading PyYAML-3.12.tar.gz (253kB)
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "c:\users\appveyor\appdata\local\temp\1\pip-build-oys1qv\PyYAML\setup.py", line 83, in <module>
from wheel.bdist_wheel import bdist_wheel
File "c:\projects\pywikibot-g4xqx\env\lib\site-packages\wheel\bdist_wheel.py", line 407
ignore=lambda x, y: {'PKG-INFO', 'requires.txt', 'SOURCES.txt',
^
SyntaxError: invalid syntax
--------------------------------
```
It's a requirement of vcrpy (T184081).