"tarbell newproject" encounter error,how to fix it?

[luckypoem]

hi.

root@AR:/usr/local/tarbell-site# pip install requests==2.3.0
Requirement already satisfied (use --upgrade to upgrade): requests==2.3.0 in /usr/local/lib/python2.7/dist-packages
root@AR:/usr/local/tarbell-site# tarbell newproject
Traceback (most recent call last):
File "/usr/local/bin/tarbell", line 5, in
from pkg_resources import load_entry_point
File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2707, in
working_set.require(requires)
File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 686, in require
needed = self.resolve(parse_requirements(requirements))
File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 584, in resolve
raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: requests==2.3.0
root@AR:/usr/local/tarbell-site#

thank you