Blender GPencil Add Onionskin Toggle to Header Addon

bl_info = {
    "name": "Add Onionskin to Header",
    "author": "Matt Thompson",
    "version": (1, 0),
    "blender": (4, 0, 2),
    "location": "",
    "description": "Adds the GPencil Onionskin overlay toggle to the view3D header",
    "warning": "",
    "doc_url": "",
    "category": "Grease Pencil",
}
import bpy


def draw_onionskin_prop(self, context):
    self.layout.prop(context.area.spaces.active.overlay, "use_gpencil_onion_skin", icon='ONIONSKIN_ON',text='')

def register():
    bpy.types.VIEW3D_HT_header.append(draw_onionskin_prop)


def unregister():
    bpy.types.VIEW3D_HT_header.remove(draw_onionskin_prop)


if __name__ == "__main__":
    register()