Internal server error while creating vnf

"Request Failed: internal server error while processing your request" coming on creating a VNF.

stack@ubuntu:~$ tacker vnf-create --vnfd-id b921150e-77d1-4772-a7ac-5cca96d1aa14 sample
Request Failed: internal server error while processing your request.

stack@ubuntu:~$ tacker vnfd-list
+--------------------------------------+--------+-----------------+--------------+
| id | name | template_source | description |
+--------------------------------------+--------+-----------------+--------------+
| b921150e-77d1-4772-a7ac-5cca96d1aa14 | sample | onboarded | Demo example |
+--------------------------------------+--------+-----------------+--------------+
stack@ubuntu:~$

stack@ubuntu:~$ tacker vim-list
+----------------------+----------------------+------+-----------+-------------+----------------------+----------------------+-------------------------+-----------+
| id | tenant_id | name | type | description | auth_url | placement_attr | auth_cred | status |
+----------------------+----------------------+------+-----------+-------------+----------------------+----------------------+-------------------------+-----------+
| f1e59b77-3ce2-4ade-b | 7f147aae7f7742c19b7e | VIM0 | openstack | | http://localhost:500 | {u'regions': | {u'username': | REACHABLE |
| 832-b9430247f545 | 4367da4a7b91 | | | | 0/v3 | [u'RegionOne']} | u'tacker', u'password': | |
| | | | | | | | u'***', | |
| | | | | | | | u'project_name': | |
| | | | | | | | u'service', | |
| | | | | | | | u'user_domain_name': | |
| | | | | | | | u'Default', | |
| | | | | | | | u'auth_url': u'http://l | |
| | | | | | | | ocalhost:5000/v3', | |
| | | | | | | | u'project_id': None, | |
| | | | | | | | u'project_domain_name': | |
| | | | | | | | u'Default'} | |
+----------------------+----------------------+------+-----------+-------------+----------------------+----------------------+-------------------------+-----------+
stack@ubuntu:~$

Tacker Logs Error:

2017-03-16 03:30:36.570 5840 ERROR tacker.api.v1.resource HTTPInternalServerError: ERROR: cannot import name python_2_unicode_compatible
2017-03-16 03:30:36.570 5840 ERROR tacker.api.v1.resource

Setup Details:

stack@ubuntu:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.5 LTS
Release: 14.04
Codename: trusty

stack@ubuntu:~$ tacker --version
0.9.1