Atom.Object.defineProperty.get is deprecated.

[dimitrioschr]

atom.workspaceView is no longer available.
In most cases you will not need the view. See the Workspace docs for
alternatives: https://atom.io/docs/api/latest/Workspace.
If you do need the view, please use atom.views.getView(atom.workspace),
which returns an HTMLElement.

Atom.Object.defineProperty.get (/Applications/Atom.app/Contents/Resources/app/src/atom.js:54:11)
<unknown> (/Users/dimitrios/.atom/packages/flake8/lib/flake8.coffee:25:11)