octoprint update errpr

Installing build dependencies: finished with status 'error'
ERROR: Command errored out with exit status 1:
command: /home/pi/OctoPrint/venv/bin/python2 /home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-wklrx7/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple --extra-index-url https://www.piwheels.org/simple -- setuptools wheel Cython
cwd: None
Complete output (26 lines):
Traceback (most recent call last):
File "/usr/lib/python2.7/runpy.py", line 174, in _run_module_as_main
"__main__", fname, loader, pkg_name)
File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
exec code in run_globals
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/__main__.py", line 19, in <module>
sys.exit(_main())
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/_internal/cli/main.py", line 73, in main
command = create_command(cmd_name, isolated=("--isolated" in cmd_args))
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/_internal/commands/__init__.py", line 96, in create_command
module = importlib.import_module(module_path)
File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
__import__(name)
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/_internal/commands/install.py", line 24, in <module>
from pip._internal.cli.req_command import RequirementCommand
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/_internal/cli/req_command.py", line 15, in <module>
from pip._internal.index.package_finder import PackageFinder
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/_internal/index/package_finder.py", line 21, in <module>
from pip._internal.index.collector import parse_links
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/_internal/index/collector.py", line 12, in <module>
from pip._vendor import html5lib, requests
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/_vendor/requests/__init__.py", line 43, in <module>
from pip._vendor import urllib3
File "/home/pi/OctoPrint/venv/lib/python2.7/site-packages/pip/_vendor/urllib3/__init__.py", line 21, in <module>
from logging import NullHandler
ImportError: cannot import name NullHandler
----------------------------------------
ERROR: Command errored out with exit status 1: /home/pi/OctoPrint/venv/bin/python2 /home/pi/OctoPrint/venv/local/lib/python2.7/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-wklrx7/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple --extra-index-url https://www.piwheels.org/simple -- setuptools wheel Cython Check the logs for full command output.
The update did not finish successfully. Please consult <code>octoprint.log</code> and <code>plugin_softwareupdate_console.log</code> for details.