我在安装joern最后一步，sudo python2 setup.py install，但是报以下错误，怎么解决：
Processing pygraphviz-1.7.zip
Writing /tmp/easy_install-hkgeHx/pygraphviz-1.7/setup.cfg
Running pygraphviz-1.7/setup.py -q bdist_egg --dist-dir /tmp/easy_install-hkgeHx/pygraphviz-1.7/egg-dist-tmp-sMccVZ
Traceback (most recent call last):
File "setup.py", line 29, in <module>
zip_safe = False
File "/usr/lib/python2.7/distutils/core.py", line 151, in setup
dist.run_commands()
File "/usr/lib/python2.7/distutils/dist.py", line 953, in run_commands
self.run_command(cmd)
File "/usr/lib/python2.7/distutils/dist.py", line 972, in run_command
cmd_obj.run()
File "/usr/lib/python2.7/dist-packages/setuptools/command/install.py", line 67, in run
self.do_egg_install()
File "/usr/lib/python2.7/dist-packages/setuptools/command/install.py", line 117, in do_egg_install
cmd.run()
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 414, in run
self.easy_install(spec, not self.no_deps)
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 644, in easy_install
return self.install_item(None, spec, tmpdir, deps, True)
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 695, in install_item
self.process_distribution(spec, dist, deps)
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 740, in process_distribution
[requirement], self.local_index, self.easy_install
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 826, in resolve
dist = best[req.key] = env.best_match(req, ws, installer)
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 1092, in best_match
return self.obtain(req, installer)
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 1104, in obtain
return installer(requirement)
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 663, in easy_install
return self.install_item(spec, dist.location, tmpdir, deps)
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 693, in install_item
dists = self.install_eggs(spec, download, tmpdir)
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 873, in install_eggs
return self.build_and_install(setup_script, setup_base)
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 1101, in build_and_install
self.run_setup(setup_script, setup_base, args)
File "/usr/lib/python2.7/dist-packages/setuptools/command/easy_install.py", line 1087, in run_setup
run_setup(setup_script, args)
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 246, in run_setup
raise
File "/usr/lib/python2.7/contextlib.py", line 35, in __exit__
self.gen.throw(type, value, traceback)
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 195, in setup_context
yield
File "/usr/lib/python2.7/contextlib.py", line 35, in __exit__
self.gen.throw(type, value, traceback)
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 166, in save_modules
saved_exc.resume()
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 141, in resume
six.reraise(type, exc, self._tb)
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 154, in save_modules
yield saved
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 195, in setup_context
yield
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 243, in run_setup
DirectorySandbox(setup_dir).run(runner)
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 273, in run
return func()
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 242, in runner
_execfile(setup_script, ns)
File "/usr/lib/python2.7/dist-packages/setuptools/sandbox.py", line 45, in _execfile
code = compile(script, filename, 'exec')
File "/tmp/easy_install-hkgeHx/pygraphviz-1.7/setup.py", line 57
docdirbase = f"share/doc/pygraphviz-{version}"
^
SyntaxError: invalid syntax
因为跑别人的实验，要求使用joern0.3.1，而这个软件又要求在python2.7环境下，所以不能修改python版本。求大神指教，谢谢了。
