pip install abjad to install Abjad into your Python environnment.
(3) Follow the Atom Flight Manual's instructions to download and install this package from inside Atom.
(1) Highlight a line or block of Python code that generates an illustratable Abjad object.
(2) Invoke the
abjadcompile: Illustrate command from Atom's Command Palette.
(3) A new pane should appear, containing the object's illustration.
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.