How can I set a default value on a Dynamic EnumProperty? I am trying to fix a bug in the Animation Nodes addon. 

The loop nodes has a dynamic EnumProperty and I need to select a default value. But only when the EnumProperty contains Items.

For that I need to know what the value of default is when I don't give it a value. I thought it was an empty string

selectedLoop = bpy.props.EnumProperty(
    items=getStartLoopNodeItems,
    name="Selected Loop",
    default="",
    update=updateActiveL)


but this does not have the same behaviour as if I left out the default parameter

selectedLoop = bpy.props.EnumProperty(
    items=getStartLoopNodeItems,
    name="Selected Loop",
    update=updateActiveL)


Does anyone know what I have to pass to default in order to have the same behaviour?



EDIT: I discovered that when I add the default parameter the EnumProperty is not created apparently because when I try to add it to the layout later it gives me this error:

rna_uiItemR: property not found: mn_LoopCallerNode.selectedLoop
/home/mathieu/.config/blender/2.73/scripts/addons/animation-nodes/nodes/system/mn_loop_caller.py:66
There is no default when items is a function (you'll get an error if you try to specify it).

I'll update the doc, this info is missing currently…

Note even with 'static' enums, not specifying the default is not the same as giving "" or None, currently. Not very pythonic, but a consequence of our current C &lt;-> python code.