Python pip doesn't work on Linux mint

I have had this error for a year now and still can't find a solution. I am using Linux Mint 17.3 Every time I try to install something using pip, I get a bunch of exceptions.

$ pip install -U scikit-learns
Exception:
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/commands/install.py", line 272, in run
    with self._build_session(options) as session:
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/basecommand.py", line 72, in _build_session
    insecure_hosts=options.trusted_hosts,
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/download.py", line 329, in __init__
    self.headers["User-Agent"] = user_agent()
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/download.py", line 93, in user_agent
    from pip._vendor import distro
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/_vendor/distro.py", line 1050, in <module>
    _distro = LinuxDistribution()
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/_vendor/distro.py", line 594, in __init__
    if include_lsb else {}
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/_vendor/distro.py", line 933, in _get_lsb_release_info
    raise subprocess.CalledProcessError(code, cmd, stdout)
CalledProcessError: Command 'lsb_release -a' returned non-zero exit status 1
Traceback (most recent call last):
  File "/usr/local/bin/pip", line 9, in <module>
    load_entry_point('pip==9.0.1', 'console_scripts', 'pip')()
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/__init__.py", line 233, in main
    return command.main(cmd_args)
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/basecommand.py", line 251, in main
    timeout=min(5, options.timeout)) as session:
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/basecommand.py", line 72, in _build_session
    insecure_hosts=options.trusted_hosts,
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/download.py", line 329, in __init__
    self.headers["User-Agent"] = user_agent()
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/download.py", line 93, in user_agent
    from pip._vendor import distro
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/_vendor/distro.py", line 1050, in <module>
    _distro = LinuxDistribution()
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/_vendor/distro.py", line 594, in __init__
    if include_lsb else {}
  File "/usr/local/lib/python2.7/dist-packages/pip-9.0.1-py2.7.egg/pip/_vendor/distro.py", line 933, in _get_lsb_release_info
    raise subprocess.CalledProcessError(code, cmd, stdout)
subprocess.CalledProcessError: Command 'lsb_release -a' returned non-zero exit status 1

The "Command 'lsb_release -a' returned non-zero exit status 1" always popped up. I have installed multiple versions of python and tried deleting them manually and it still comes up with the same error.

If you can't help me solve this error, how can I uninstall all python files?

When I update Python and pip，I had the problem like this your can run lsb_release, if your run shell: #lsb_release

It work like: