When running ansinle-playbook, an exception always happens.

Surprizingly, if I try to evaluate the statement that causes the exception in an interpreter, no error happens:

$ python
Python 2.7.11 (default, Apr 15 2016, 13:09:43) 
[GCC 5.3.1 20151207 (ALT Linux 5.3.1-alt3)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> sub = "playbook"
>>> myclass = "%sCLI" % sub.capitalize()
>>> myclass
'PlaybookCLI'
>>> getattr(__import__("ansible.cli.%s" % sub, fromlist=[myclass]), myclass)
<class 'ansible.cli.playbook.PlaybookCLI'>
>>> 



$ rpm -qf "$(which ansible-playbook)"
ansible-2.0.2.0-alt2
$ ansible-playbook
ERROR! Unexpected Exception: 'module' object has no attribute '_vendor'
the full traceback was:

Traceback (most recent call last):
  File "/usr/bin/ansible-playbook", line 73, in <module>
    mycli = getattr(__import__("ansible.cli.%s" % sub, fromlist=[myclass]), myclass)
  File "/usr/lib/python2.7/site-packages/ansible/cli/playbook.py", line 30, in <module>
    from ansible.executor.playbook_executor import PlaybookExecutor
  File "/usr/lib/python2.7/site-packages/ansible/executor/playbook_executor.py", line 27, in <module>
    from ansible.executor.task_queue_manager import TaskQueueManager
  File "/usr/lib/python2.7/site-packages/ansible/executor/task_queue_manager.py", line 28, in <module>
    from ansible.executor.play_iterator import PlayIterator
  File "/usr/lib/python2.7/site-packages/ansible/executor/play_iterator.py", line 29, in <module>
    from ansible.playbook.block import Block
  File "/usr/lib/python2.7/site-packages/ansible/playbook/__init__.py", line 25, in <module>
    from ansible.playbook.play import Play
  File "/usr/lib/python2.7/site-packages/ansible/playbook/play.py", line 27, in <module>
    from ansible.playbook.base import Base
  File "/usr/lib/python2.7/site-packages/ansible/playbook/base.py", line 35, in <module>
    from ansible.parsing.dataloader import DataLoader
  File "/usr/lib/python2.7/site-packages/ansible/parsing/dataloader.py", line 32, in <module>
    from ansible.parsing.vault import VaultLib
  File "/usr/lib/python2.7/site-packages/ansible/parsing/vault/__init__.py", line 67, in <module>
    from cryptography.hazmat.primitives.hashes import SHA256 as c_SHA256
  File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/primitives/hashes.py", line 15, in <module>
    from cryptography.hazmat.backends.interfaces import HashBackend
  File "/usr/lib64/python2.7/site-packages/cryptography/hazmat/backends/__init__.py", line 7, in <module>
    import pkg_resources
  File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 90, in <module>
    packaging = pkg_resources._vendor.packaging
AttributeError: 'module' object has no attribute '_vendor'
$