Ecco la mia soluzione basata sul link condiviso da @sansSpoon:
Puoi usare questa lib di python: FinderSidebarEditor
Semplicemente inseriscilo nel tuo percorso python, quindi in python puoi modificare facilmente la tua barra laterale del Finder:
#!/usr/bin/python
from FinderSidebarEditor import FinderSidebar # Import the module
sidebar = FinderSidebar() # Create a Finder sidebar instance to act on.
sidebar.remove("All My Files") # Remove 'All My Files' favorite from sidebar
sidebar.remove("iCloud") # Remove 'iCloud' favorite from sidebar
sidebar.add("/Library") # Add '/Library' favorite to sidebar
sidebar.add("/SomeShare", uri="smb://shares") # Mount 'smb://shares/SomeShare' to '/Volumes/SomeShare' and add as favorite to sidebar
sidebar.add("/SomeOtherShare", uri="afp://username:pw@server") # Mount pw protected 'afp://server/SomeOtherShare' to '/Volumes/SomeOtherShare' and add as favorite to sidebar
sidebar.move("Library", "Applications") # Move 'Library' favorite to slot just below 'Applications'