Traceback (most recent call last):
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/bin/pip", line 5, in <module>
    from pip._internal.cli.main import main
ModuleNotFoundError: No module named 'pip'

source_venv() {
  VENV_DIR=$1
  if [[ "${VIRTUAL_ENV}" == "" ]]; then
    if [[ ! -d "${VENV_DIR}"/venv ]]; then
      virtualenv "${VENV_DIR}"/venv --python=python3 --system-site-packages
    fi
    source "${VENV_DIR}"/venv/bin/activate
  else
    echo "Found existing virtualenv"
  fi
}

Traceback (most recent call last):
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/flake8/checker.py", line 451, in run_check
    return plugin["plugin"](**arguments)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/flake8/plugins/pyflakes.py", line 99, in __init__
    super(FlakesChecker, self).__init__(
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/pyflakes/checker.py", line 497, in __init__
    self.handleChildren(tree)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/pyflakes/checker.py", line 824, in handleChildren
    self.handleNode(node, tree)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/pyflakes/checker.py", line 871, in handleNode
    handler(node)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/pyflakes/checker.py", line 824, in handleChildren
    self.handleNode(node, tree)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/pyflakes/checker.py", line 871, in handleNode
    handler(node)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/pyflakes/checker.py", line 824, in handleChildren
    self.handleNode(node, tree)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/pyflakes/checker.py", line 870, in handleNode
    handler = self.getNodeHandler(node.__class__)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/pyflakes/checker.py", line 700, in getNodeHandler
    self._nodeHandlers[node_class] = handler = getattr(self, nodeType)
AttributeError: 'FlakesChecker' object has no attribute 'CONSTANT'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.8/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/flake8/checker.py", line 682, in _run_checks
    return checker.run_checks()
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/flake8/checker.py", line 612, in run_checks
    self.run_ast_checks()
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/flake8/checker.py", line 513, in run_ast_checks
    checker = self.run_check(plugin, tree=ast)
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/flake8/checker.py", line 456, in run_check
    raise exceptions.PluginExecutionFailed(
  File "/usr/local/google/home/qqin/github/nighthawk/tools/pyformat/venv/lib/python3.8/site-packages/flake8/exceptions.py", line 86, in __init__
    self.original_exception = kwargs.pop("exception")
KeyError: 'exception'