Python에서 "가져오기 오류"를 해결하는 방법은 무엇입니까?

필수 모듈이 설치되었지만 lxml가져오는 동안 오류가 발생했습니다.ImportError: No module named lxml

내가 어떻게 알아

1. Python 모듈을 어디에서 고려해야 합니까?
2. 어떤 Python 버전과 pip를 사용하거나 설정하고 있나요?

이 문제를 이해하고 해결하도록 도와주세요.

uname -a
Linux machine-name 4.4.0-31-generic #50~14.04.1-Ubuntu SMP Wed Jul 13 01:07:32 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

which python
/usr/local/bin/python

which pip
/usr/local/bin/pip

pip --version
/usr/local/lib/python2.7/dist-packages/cryptography/hazmat/primitives/constant_time.py:26: CryptographyDeprecationWarning: Support for your Python version is deprecated. The next version of cryptography will remove support. Please upgrade to a release (2.7.7+) that supports hmac.compare_digest as soon as possible.
  utils.PersistentlyDeprecated2018,
pip 18.1 from /usr/local/lib/python2.7/dist-packages/pip (python 2.7)

python
Python 2.7.16 (default, May  6 2020, 13:05:58) 
[GCC 4.8.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> import urllib2
>>> os.path.abspath(urllib2.__file__)
'/usr/local/lib/python2.7/urllib2.pyc'

echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

echo $PYTHONPATH
doesn't display anything (empty)


ls -ls /usr/bin/python*

   0 lrwxrwxrwx 1 root root       9  /usr/bin/python -> python2.7
   0 lrwxrwxrwx 1 root root      16  /usr/bin/python-config -> python2.7-config
   0 lrwxrwxrwx 1 root root       9  /usr/bin/python2 -> python2.7
   0 lrwxrwxrwx 1 root root      16  /usr/bin/python2-config -> python2.7-config
3264 -rwxr-xr-x 1 root root 3341288  /usr/bin/python2.7
   0 lrwxrwxrwx 1 root root      33  /usr/bin/python2.7-config -> x86_64-linux-gnu-python2.7-config
   0 lrwxrwxrwx 1 root root       9  /usr/bin/python3 -> python3.4
3628 -rwxr-xr-x 2 root root 3714088  /usr/bin/python3.4
3628 -rwxr-xr-x 2 root root 3714088  /usr/bin/python3.4m
   0 lrwxrwxrwx 1 root root      10  /usr/bin/python3m -> python3.4m
   
ls -ls /usr/local/bin/python*
   0 lrwxrwxrwx 1 root root       9  /usr/local/bin/python -> python2.7
   0 lrwxrwxrwx 1 root root      14  /usr/local/bin/python-config -> python2-config
   0 lrwxrwxrwx 1 root root       7  /usr/local/bin/python.orig -> python2
   0 lrwxrwxrwx 1 root root       9  /usr/local/bin/python2 -> python2.7
   0 lrwxrwxrwx 1 root root      16  /usr/local/bin/python2-config -> python2.7-config
8280 -rwxr-xr-x 1 root root 8478000  /usr/local/bin/python2.7
   4 -rwxr-xr-x 1 root root    1687  /usr/local/bin/python2.7-config

find /bin /usr /lib* /home -type f -name "pip*" -executable
/usr/local/bin/pip
/usr/local/bin/pip2.7
/usr/local/bin/pip2
/usr/bin/pip
/usr/bin/pip2

/usr/bin/pip install lxml
Requirement already satisfied (use --upgrade to upgrade): lxml in /usr/local/lib/python2.7/dist-packages
Cleaning up...

/usr/bin/pip2 install lxml
Requirement already satisfied (use --upgrade to upgrade): lxml in /usr/local/lib/python2.7/dist-packages
Cleaning up...

/usr/local/bin/pip2 install lxml
/usr/local/lib/python2.7/dist-packages/cryptography/hazmat/primitives/constant_time.py:26: CryptographyDeprecationWarning: Support for your Python version is deprecated. The next version of cryptography will remove support. Please upgrade to a release (2.7.7+) that supports hmac.compare_digest as soon as possible.
  utils.PersistentlyDeprecated2018,
Requirement already satisfied: lxml in /usr/local/lib/python2.7/dist-packages (4.6.3)

/usr/local/bin/pip2.7 install lxml
/usr/local/lib/python2.7/dist-packages/cryptography/hazmat/primitives/constant_time.py:26: CryptographyDeprecationWarning: Support for your Python version is deprecated. The next version of cryptography will remove support. Please upgrade to a release (2.7.7+) that supports hmac.compare_digest as soon as possible.
  utils.PersistentlyDeprecated2018,
Requirement already satisfied: lxml in /usr/local/lib/python2.7/dist-packages (4.6.3)

/usr/local/bin/pip install lxml
/usr/local/lib/python2.7/dist-packages/cryptography/hazmat/primitives/constant_time.py:26: CryptographyDeprecationWarning: Support for your Python version is deprecated. The next version of cryptography will remove support. Please upgrade to a release (2.7.7+) that supports hmac.compare_digest as soon as possible.
  utils.PersistentlyDeprecated2018,
Requirement already satisfied: lxml in /usr/local/lib/python2.7/dist-packages (4.6.3)

sudo pip install lxml
/usr/local/lib/python2.7/dist-packages/cryptography/hazmat/primitives/constant_time.py:26: CryptographyDeprecationWarning: Support for your Python version is deprecated. The next version of cryptography will remove support. Please upgrade to a release (2.7.7+) that supports hmac.compare_digest as soon as possible.
  utils.PersistentlyDeprecated2018,
The directory '/home/abcd/.cache/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
The directory '/home/abcd/.cache/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Requirement already satisfied: lxml in /usr/local/lib/python2.7/dist-packages (4.6.3)

python -m pip install lxml
/usr/local/bin/python: No module named pip

python
Python 2.7.16 (default, May  6 2020, 13:05:58) 
[GCC 4.8.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import lxml
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named lxml

import sys
print("\n".join(sys.path))

/usr/local/lib/python27.zip
/usr/local/lib/python2.7
/usr/local/lib/python2.7/plat-linux2
/usr/local/lib/python2.7/lib-tk
/usr/local/lib/python2.7/lib-old
/usr/local/lib/python2.7/lib-dynload
/usr/local/lib/python2.7/site-packages