pip3 повреждается; требует sudo

Я уведомление pip3 повреждаюсь, если не выполнено sudo; даже после попытки произвести чистку и переустановить:

sudo apt-get purge python3-pip
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  golang-1.6-go golang-1.6-src python3-wheel
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED
  python3-pip*
0 to upgrade, 0 to newly install, 1 to remove and 67 not to upgrade.
After this operation, 569 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 394962 files and directories currently installed.)
Removing python3-pip (8.1.1-2ubuntu0.4) ...
Processing triggers for man-db (2.7.5-1) ...

where pip3
pip3 not found

sudo apt-get install python3-pip
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  golang-1.6-go golang-1.6-src
Use 'sudo apt autoremove' to remove them.
The following NEW packages will be installed
  python3-pip
0 to upgrade, 1 to newly install, 0 to remove and 67 not to upgrade.
Need to get 0 B/109 kB of archives.
After this operation, 569 kB of additional disk space will be used.
Selecting previously unselected package python3-pip.
(Reading database ... 394889 files and directories currently installed.)
Preparing to unpack .../python3-pip_8.1.1-2ubuntu0.4_all.deb ...
Unpacking python3-pip (8.1.1-2ubuntu0.4) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up python3-pip (8.1.1-2ubuntu0.4) ...

pip3
Traceback (most recent call last):
  File "/usr/bin/pip3", line 9, in <module>
    from pip import main
  File "/usr/local/lib/python2.7/dist-packages/pip/__init__.py", line 28, in <module>
    from pip.vcs import git, mercurial, subversion, bazaar  # noqa
  File "/usr/local/lib/python2.7/dist-packages/pip/vcs/subversion.py", line 9, in <module>
    from pip.index import Link
  File "/usr/local/lib/python2.7/dist-packages/pip/index.py", line 31, in <module>
    from pip.wheel import Wheel, wheel_ext
  File "/usr/local/lib/python2.7/dist-packages/pip/wheel.py", line 6, in <module>
    import compileall
  File "/usr/lib/python3.5/compileall.py", line 20, in <module>
    from concurrent.futures import ProcessPoolExecutor
  File "/usr/local/lib/python2.7/dist-packages/concurrent/futures/__init__.py", line 8, in <module>
    from concurrent.futures._base import (FIRST_COMPLETED,
  File "/usr/local/lib/python2.7/dist-packages/concurrent/futures/_base.py", line 381
    raise exception_type, self._exception, self._traceback
                        ^
SyntaxError: invalid syntax

python3 --version
Python 3.5.2

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 16.04.2 LTS
Release:        16.04
Codename:       xenial

sudo pip3

Usage:   
  pip <command> [options]

Это дизайном, что я должен использовать sudo для выполнения pip3?

p.s. Я не могу создать тег pip3 из-за точек, но не стесняться повторно отмечать как pip3