If you want to interact with OS X's Accessibility APIs from Python then try atomac. System Events is just an AppleScriptable wrapper around various system APIs, but PyObjC and other Python libraries already give you extensive access to the system APIs without having to deal with any AS/SB nonsense.
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p.s You may need to enable the 'assistive devices' option in System Preferences' Accessibility pane, otherwise most accessibility features won't be available.