我正在尝试安装lxml在Mac（v 10.9.4）上安装scrapy
╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ pip install lxml Downloading/unpacking lxml Downloading lxml-3.4.0.tar.gz (3.5MB): 3.5MB downloaded Running setup.py (path:/private/var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip_build_ishaantaylor/lxml/setup.py) egg_info for package lxml /System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'bugtrack_url' warnings.warn(msg) Building lxml version 3.4.0. Building without Cython. Using build configuration of libxslt 1.1.28 warning: no previously-included files found matching '*.py' Installing collected packages: lxml Running setup.py install for lxml /System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'bugtrack_url' warnings.warn(msg) Building lxml version 3.4.0. Building without Cython. Using build configuration of libxslt 1.1.28 building 'lxml.etree' extension cc -fno-strict-aliasing -fno-common -dynamic -arch x86_64 -arch i386 -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch x86_64 -arch i386 -pipe -I/usr/include/libxml2 -I/private/var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip_build_ishaantaylor/lxml/src/lxml/includes -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c src/lxml/lxml.etree.c -o build/temp.macosx-10.9-intel-2.7/src/lxml/lxml.etree.o -w -flat_namespace cc -bundle -undefined dynamic_lookup -arch x86_64 -arch i386 -Wl,-F. build/temp.macosx-10.9-intel-2.7/src/lxml/lxml.etree.o -lxslt -lexslt -lxml2 -lz -lm -o build/lib.macosx-10.9-intel-2.7/lxml/etree.so building 'lxml.objectify' extension cc -fno-strict-aliasing -fno-common -dynamic -arch x86_64 -arch i386 -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch x86_64 -arch i386 -pipe -I/usr/include/libxml2 -I/private/var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip_build_ishaantaylor/lxml/src/lxml/includes -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c src/lxml/lxml.objectify.c -o build/temp.macosx-10.9-intel-2.7/src/lxml/lxml.objectify.o -w -flat_namespace cc -bundle -undefined dynamic_lookup -arch x86_64 -arch i386 -Wl,-F. build/temp.macosx-10.9-intel-2.7/src/lxml/lxml.objectify.o -lxslt -lexslt -lxml2 -lz -lm -o build/lib.macosx-10.9-intel-2.7/lxml/objectify.so error: could not create '/lib/python2.7/site-packages/lxml': Permission denied Complete output from command /usr/bin/python -c "import setuptools, tokenize;__file__='/private/var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip_build_ishaantaylor/lxml/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip-_xm20j-record/install-record.txt --single-version-externally-managed --compile: /System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'bugtrack_url' warnings.warn(msg) Building lxml version 3.4.0. Building without Cython. Using build configuration of libxslt 1.1.28 running install running build running build_py creating build creating build/lib.macosx-10.9-intel-2.7 creating build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/__init__.py -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/_elementpath.py -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/builder.py -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/cssselect.py -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/doctestcompare.py -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/ElementInclude.py -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/pyclasslookup.py -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/sax.py -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/usedoctest.py -> build/lib.macosx-10.9-intel-2.7/lxml creating build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/__init__.py -> build/lib.macosx-10.9-intel-2.7/lxml/includes creating build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/__init__.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/_diffcommand.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/_html5builder.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/_setmixin.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/builder.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/clean.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/defs.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/diff.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/ElementSoup.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/formfill.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/html5parser.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/soupparser.py -> build/lib.macosx-10.9-intel-2.7/lxml/html copying src/lxml/html/usedoctest.py -> build/lib.macosx-10.9-intel-2.7/lxml/html creating build/lib.macosx-10.9-intel-2.7/lxml/isoschematron copying src/lxml/isoschematron/__init__.py -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron copying src/lxml/lxml.etree.h -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/lxml.etree_api.h -> build/lib.macosx-10.9-intel-2.7/lxml copying src/lxml/includes/c14n.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/config.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/dtdvalid.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/etreepublic.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/htmlparser.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/relaxng.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/schematron.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/tree.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/uri.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/xinclude.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/xmlerror.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/xmlparser.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/xmlschema.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/xpath.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/xslt.pxd -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/etree_defs.h -> build/lib.macosx-10.9-intel-2.7/lxml/includes copying src/lxml/includes/lxml-version.h -> build/lib.macosx-10.9-intel-2.7/lxml/includes creating build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources creating build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/rng copying src/lxml/isoschematron/resources/rng/iso-schematron.rng -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/rng creating build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl copying src/lxml/isoschematron/resources/xsl/RNG2Schtrn.xsl -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl copying src/lxml/isoschematron/resources/xsl/XSD2Schtrn.xsl -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl creating build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl/iso-schematron-xslt1 copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_abstract_expand.xsl -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl/iso-schematron-xslt1 copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_dsdl_include.xsl -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl/iso-schematron-xslt1 copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_schematron_message.xsl -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl/iso-schematron-xslt1 copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_schematron_skeleton_for_xslt1.xsl -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl/iso-schematron-xslt1 copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_svrl_for_xslt1.xsl -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl/iso-schematron-xslt1 copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/readme.txt -> build/lib.macosx-10.9-intel-2.7/lxml/isoschematron/resources/xsl/iso-schematron-xslt1 running build_ext building 'lxml.etree' extension creating build/temp.macosx-10.9-intel-2.7 creating build/temp.macosx-10.9-intel-2.7/src creating build/temp.macosx-10.9-intel-2.7/src/lxml cc -fno-strict-aliasing -fno-common -dynamic -arch x86_64 -arch i386 -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch x86_64 -arch i386 -pipe -I/usr/include/libxml2 -I/private/var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip_build_ishaantaylor/lxml/src/lxml/includes -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c src/lxml/lxml.etree.c -o build/temp.macosx-10.9-intel-2.7/src/lxml/lxml.etree.o -w -flat_namespace cc -bundle -undefined dynamic_lookup -arch x86_64 -arch i386 -Wl,-F. build/temp.macosx-10.9-intel-2.7/src/lxml/lxml.etree.o -lxslt -lexslt -lxml2 -lz -lm -o build/lib.macosx-10.9-intel-2.7/lxml/etree.so building 'lxml.objectify' extension cc -fno-strict-aliasing -fno-common -dynamic -arch x86_64 -arch i386 -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -fwrapv -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch x86_64 -arch i386 -pipe -I/usr/include/libxml2 -I/private/var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip_build_ishaantaylor/lxml/src/lxml/includes -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c src/lxml/lxml.objectify.c -o build/temp.macosx-10.9-intel-2.7/src/lxml/lxml.objectify.o -w -flat_namespace cc -bundle -undefined dynamic_lookup -arch x86_64 -arch i386 -Wl,-F. build/temp.macosx-10.9-intel-2.7/src/lxml/lxml.objectify.o -lxslt -lexslt -lxml2 -lz -lm -o build/lib.macosx-10.9-intel-2.7/lxml/objectify.so running install_lib creating /lib/python2.7/site-packages/lxml error: could not create '/lib/python2.7/site-packages/lxml': Permission denied ---------------------------------------- Cleaning up... Command /usr/bin/python -c "import setuptools, tokenize;__file__='/private/var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip_build_ishaantaylor/lxml/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip-_xm20j-record/install-record.txt --single-version-externally-managed --compile failed with error code 1 in /private/var/folders/8l/t7tcq67d34v7qq_4hp3s1dm80000gn/T/pip_build_ishaantaylor/lxml Storing debug log for failure in /Users/ishaantaylor/Library/Logs/pip.log
如果有人可以帮助我，我将不胜感激！我怀疑这个问题与python的多个版本有关，但是我不确定如何检查或修复它。
编辑1：当我尝试sudo pip install lxml：
╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ sudo pip install lxml Traceback (most recent call last): File "/bin/pip", line 7, in <module> from pip import main ImportError: No module named pip
编辑2：当我尝试 STATIC_DEPS=true sudo pip install lxml
╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ STATIC_DEPS=true sudo pip install lxml Traceback (most recent call last): File "/bin/pip", line 7, in <module> from pip import main ImportError: No module named pip
另外，我尝试用pip安装另一个软件包，但也没有用..见下文：
╭─ishaantaylor@Ishaans-MacBook-Pro.local /lib/python2.7/site-packages ╰─➤ pip install requests Downloading/unpacking requests Downloading requests-2.4.1-py2.py3-none-any.whl (458kB): 458kB downloaded Installing collected packages: requests Cleaning up... Exception: Traceback (most recent call last): File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/basecommand.py", line 122, in main status = self.run(options, args) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/commands/install.py", line 283, in run requirement_set.install(install_options, global_options, root=options.root_path) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 1435, in install requirement.install(install_options, global_options, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 671, in install self.move_wheel_files(self.source_dir, root=root) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 901, in move_wheel_files pycompile=self.pycompile, File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/wheel.py", line 215, in move_wheel_files clobber(source, lib_dir, True) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/wheel.py", line 205, in clobber os.makedirs(destdir) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/os.py", line 157, in makedirs mkdir(name, mode) OSError: [Errno 13] Permission denied: '/lib/python2.7/site-packages/requests' Storing debug log for failure in /Users/ishaantaylor/Library/Logs/pip.log
编辑4：尝试下载virtualenv，人们建议将此作为sudo的替代。结果如下：
╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ pip install virtualenv 127 ↵ Downloading/unpacking virtualenv Downloading virtualenv-1.11.6-py2.py3-none-any.whl (1.6MB): 1.6MB downloaded Installing collected packages: virtualenv Cleaning up... Exception: Traceback (most recent call last): File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/basecommand.py", line 122, in main status = self.run(options, args) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/commands/install.py", line 283, in run requirement_set.install(install_options, global_options, root=options.root_path) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 1435, in install requirement.install(install_options, global_options, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 671, in install self.move_wheel_files(self.source_dir, root=root) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 901, in move_wheel_files pycompile=self.pycompile, File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/wheel.py", line 215, in move_wheel_files clobber(source, lib_dir, True) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/wheel.py", line 209, in clobber shutil.copy2(srcfile, destfile) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 130, in copy2 copyfile(src, dst) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 83, in copyfile with open(dst, 'wb') as fdst: IOError: [Errno 13] Permission denied: '/lib/python2.7/site-packages/virtualenv.py' Storing debug log for failure in /Users/ishaantaylor/Library/Logs/pip.log
编辑5：
╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ sudo pip install virtualenv 1 ↵ Password: Traceback (most recent call last): File "/bin/pip", line 7, in <module> from pip import main ImportError: No module named pip ╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ pip install virtualenv 1 ↵ Downloading/unpacking virtualenv Downloading virtualenv-1.11.6-py2.py3-none-any.whl (1.6MB): 1.6MB downloaded Installing collected packages: virtualenv Cleaning up... Exception: Traceback (most recent call last): File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/basecommand.py", line 122, in main status = self.run(options, args) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/commands/install.py", line 283, in run requirement_set.install(install_options, global_options, root=options.root_path) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 1435, in install requirement.install(install_options, global_options, *args, **kwargs) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 671, in install self.move_wheel_files(self.source_dir, root=root) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/req.py", line 901, in move_wheel_files pycompile=self.pycompile, File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/wheel.py", line 215, in move_wheel_files clobber(source, lib_dir, True) File "/usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/wheel.py", line 209, in clobber shutil.copy2(srcfile, destfile) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 130, in copy2 copyfile(src, dst) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 83, in copyfile with open(dst, 'wb') as fdst: IOError: [Errno 13] Permission denied: '/lib/python2.7/site-packages/virtualenv.py' Storing debug log for failure in /Users/ishaantaylor/Library/Logs/pip.log
编辑6：回应hd1：
╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ curl -kLso /tmp/get-pip.py https://bootstrap.pypa.io/get-pip.py ╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ sudo python get-pip.py python: can't open file 'get-pip.py': [Errno 2] No such file or directory
编辑7：回应hd1：
╭─ishaantaylor@Ishaans-MacBook-Pro.local / ╰─➤ curl -kLso /tmp/get-pip.py https://bootstrap.pypa.io/get-pip.py ╭─ishaantaylor@Ishaans-MacBook-Pro.local / ╰─➤ cd ~ ╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ sudo python /tmp/get-pip.py Requirement already up-to-date: pip in /usr/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg Cleaning up... ╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ sudo pip install virtualenv Downloading/unpacking virtualenv Downloading virtualenv-1.11.6-py2.py3-none-any.whl (1.6MB): 1.6MB downloaded Installing collected packages: virtualenv Successfully installed virtualenv Cleaning up... ╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ mkdir -p ~/.virtualenvs ╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ virtualenv ~/.virtualenvs/lxmltest Traceback (most recent call last): File "/bin/virtualenv", line 7, in <module> from virtualenv import main ImportError: No module named virtualenv ╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ which virtualenv 1 ↵ /bin/virtualenv ╭─ishaantaylor@Ishaans-MacBook-Pro.local ~ ╰─➤ echo -e ${PATH//:/\\n} /usr/local/bin /usr/bin /bin /usr/sbin /sbin /opt/X11/bin
根据输出中的以下消息，你似乎遇到了权限错误error: could not create '/lib/python2.7/site-packages/lxml': Permission denied。
error: could not create '/lib/python2.7/site-packages/lxml': Permission denied
你可以尝试做的一件事是使用来对软件包进行用户安装pip install lxml --user。
pip install lxml --user
你也可以pip install以超级用户身份运行，sudo pip install lxml但通常不是一个好主意，因为它可能会导致系统级程序包出现问题。
pip install
sudo pip install lxml
