Failed to load the css-edit-groups package

Hello,

I've installed this package and get the following error.
I've overridden Keybindings as reported in your docs but still get the error every time I open Atom.

Atom: 1.25.1 x64
Electron: 1.7.11
OS: Mac OS X 10.12.6
Thrown From: css-edit-groups package 0.4.2

Stack Trace

Failed to load the css-edit-groups package

At Duplicate key 'cmd-l'

Error: Duplicate key 'cmd-l'
    at Object.detectDuplicateKeys (<embedded>:39393:19)
    at addProperty (<embedded>:171104:42)
    at Array.reduce (native)
    at Obj (<embedded>:171096:34)
    at transformNode (<embedded>:171172:18)
    at Value (<embedded>:171053:18)
    at transformNode (<embedded>:171172:18)
    at addProperty (<embedded>:171103:21)
    at Array.reduce (native)
    at Obj (<embedded>:171096:34)
    at transformNode (<embedded>:171172:18)
    at Value (<embedded>:171053:18)
    at transformNode (<embedded>:171172:18)
    at Block (<embedded>:171050:18)
    at transformNode (<embedded>:171172:18)
    at Object.parse (<embedded>:171178:22)
    at parseObject (<embedded>:39142:29)
    at parseContentsSync (<embedded>:39168:22)
    at Object.readFileSync (<embedded>:39280:20)
    at keymaps.getKeymapPaths.map (<embedded>:72732:20)
    at Array.map (native)
    at Package.loadKeymaps (<embedded>:72730:50)
    at measure (<embedded>:72411:20)
    at Package.measure (<embedded>:72366:25)
    at Package.load (<embedded>:72407:16)
    at PackageManager.loadAvailablePackage (<embedded>:25665:16)
    at config.transact (<embedded>:25578:20)
    at Config.transact (<embedded>:22338:20)
    at PackageManager.loadPackages (<embedded>:25576:23)
    at loadStatePromise.loadState.then (<embedded>:1069:27)
    at <anonymous>:null:null

Commands

Non-Core Packages

css-edit-groups 0.4.2

Start by reproducing the failure in Atom 1.25.1 with css-edit-groups 0.4.2 and inspect the package's keybinding configuration, especially the reported duplicate cmd-l entry. The work is done when the package opens without the duplicate-key error while the documented keybinding override remains usable.