Error during bench update V12

Hello,
I got this error while doing bench update today. Can you please guide me on how to fix it?

erp@Asset:/$ cd home/erp/frappe-bench/sites/erp.asset-industrial.com
erp@Asset:~/frappe-bench/sites/erp.asset-industrial.com$ vi site_config.json
erp@Asset:~/frappe-bench/sites/erp.asset-industrial.com$ vi site_config.json
erp@Asset:~/frappe-bench/sites/erp.asset-industrial.com$ vi site_config.json
erp@Asset:~/frappe-bench/sites/erp.asset-industrial.com$ vi site_config.json
erp@Asset:~/frappe-bench/sites/erp.asset-industrial.com$ cd ..
erp@Asset:~/frappe-bench/sites$ cd ..
erp@Asset:~/frappe-bench$ bench update
Traceback (most recent call last):
  File "/usr/local/bin/bench", line 11, in <module>
    load_entry_point('bench', 'console_scripts', 'bench')()
  File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 489, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2793, in load_entry_point
    return ep.load()
  File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2411, in load
    return self.resolve()
  File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2417, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/home/erp/.bench/bench/cli.py", line 4, in <module>
    from bench.app import get_apps
  File "/home/erp/.bench/bench/app.py", line 15, in <module>
    import git
  File "/usr/local/lib/python3.6/dist-packages/git/__init__.py", line 38, in <module>
    from git.exc import *                       # @NoMove @IgnorePep8
  File "/usr/local/lib/python3.6/dist-packages/git/exc.py", line 9, in <module>
    from git.compat import UnicodeMixin, safe_decode, string_types
  File "/usr/local/lib/python3.6/dist-packages/git/compat.py", line 16, in <module>
    from gitdb.utils.compat import (
ModuleNotFoundError: No module named 'gitdb.utils.compat'

Regards,
Ahmed