I can't figure out how to translate the following AppleScript into JXA (JavaScript for Automation under Mac OS X Yosemite) :

```
tell application id "com.omnigroup.OmniGraffle6"
    tell canvas of front window
        make new line at end of graphics with properties {point list:L, draws shadow:false}
    end tell
end tell

```

Here is what I've tried but this fails while executing the last line with error "AppleEvent handler failed" :

```
app = Application('OmniGraffle')

pt1 = app.Point({x:1,y:2})
pt2 = app.Point({x:1,y:2})

L = []
L.push(pt1)
L.push(pt2)

line = app.Line({pointList:L})

app.documents[0].canvases[0].lines.push(line)

```

Can anyone help ?

Thanks,
Aurelien