python2.7版本，命令“pip install lac”一直安装不上。试了一下不同的lac版本也安装不上。

pip install lac 一直报错，报错如下
Getting requirements to build wheel ... error
ERROR: Command errored out with exit status 1:
command: /data/sysdir/servers/anaconda2/bin/python /data/home/ds/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmpQgIH1c
cwd: /tmp/pip-install-ILzYqM/opencv-python
Complete output (22 lines):
Traceback (most recent call last):
File "/data/home/ds/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 280, in
main()
File "/data/home/ds/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 263, in main
json_out['return_val'] = hook(**hook_input['kwargs'])
File "/data/home/ds/.local/lib/python2.7/site-packages/pip/_vendor/pep517/_in_process.py", line 114, in get_requires_for_build_wheel
return hook(config_settings)
File "/tmp/pip-build-env-SxqOui/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 146, in get_requires_for_build_wheel
return self._get_build_requires(config_settings, requirements=['wheel'])
File "/tmp/pip-build-env-SxqOui/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 127, in _get_build_requires
self.run_setup()
File "/tmp/pip-build-env-SxqOui/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 243, in run_setup
self).run_setup(setup_script=setup_script)
File "/tmp/pip-build-env-SxqOui/overlay/lib/python2.7/site-packages/setuptools/build_meta.py", line 142, in run_setup
exec(compile(code, __file__, 'exec'), locals())
File "setup.py", line 448, in
main()
File "setup.py", line 99, in main
% {"ext": re.escape(sysconfig.get_config_var("EXT_SUFFIX"))}
File "/data/sysdir/servers/anaconda2/lib/python2.7/re.py", line 210, in escape
s = list(pattern)
TypeError: 'NoneType' object is not iterable

Start by reproducing `pip install lac` under the reported Python 2.7 environment and read the failing `opencv-python` build output. Inspect the referenced `setup.py` path and its handling of `sysconfig.get_config_var("EXT_SUFFIX")`. Done means identifying a supported installation path or documenting the environment limitation with a verified result.

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