pip3 is stopped working when I installed Python3.6

[jacocal]

pip3 command used to be working while I programmed in python3.5, after installing python3.6 it now shows this error when it runs?

  File "/usr/bin/pip3", line 9, in <module>
    from pip import main
  File "/usr/local/lib/python3.5/dist-packages/pip/__init__.py", line 26, in <module>
    from pip.utils import get_installed_distributions, get_prog
  File "/usr/local/lib/python3.5/dist-packages/pip/utils/__init__.py", line 27, in <module>
    from pip._vendor import pkg_resources
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 3018, in <module>
    @_call_aside
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 3004, in _call_aside
    f(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 3046, in _initialize_master_working_set
    dist.activate(replace=False)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 2578, in activate
    declare_namespace(pkg)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 2152, in declare_namespace
    _handle_ns(packageName, path_item)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 2092, in _handle_ns
    _rebuild_mod_path(path, packageName, module)
  File "/usr/local/lib/python3.5/dist-packages/pip/_vendor/pkg_resources/__init__.py", line 2121, in _rebuild_mod_path
    orig_path.sort(key=position_in_sys_path)
AttributeError: '_NamespacePath' object has no attribute 'sort'

I'm not an expert on this and have very little knowledge about this kind of error. Anyone able to help?

[jaraco]

The underlying issue is pypa/pip#4216. The issue has been fixed (worked around) in pkg_resources (#885), but pip has yet to incorporate the fix.

The issue is probably triggered by an improperly-installed namespace package (or directory without __init__.py in your sys.path). It's a little surprising that you encountered the issue by installing Python 3.6. My guess is your distribution, when you installed Python 3.6, changed something in your site packages. I note that pip3 is still using Python 3.5. Maybe try removing Python 3.6 and see if your pip3 starts working again.

Otherwise, the best I can recommend is to roll back to a clean Python install(s). If you can replicate the issue on a clean system and share those replication steps here, we can investigate further.