custom 3d menu to append a scene in blender from a .blend

bl_info = {"name": "yellowsubmarine",
"author": "anonb",
"version": (1, 0, 0),
"blender": (2, 72, 0),
"location": "Add > Mesh",
"description": "Create yellowsubmarine primitive.",
"warning": "",
"wiki_url": "",
"tracker_url": "",
"category": "Add Mesh"}




if "bpy" in locals():
import imp




import bpy
import bmesh
import math
from mathutils import *




class OBJECT_OT_addSubmarine(bpy.types.Operator):
'''
Class representing an operator for adding a yellow submarine
'''
bl_idname = "mesh.addsubmarine" #name used to refer to this operator
bl_label = "Add Submarine" #operator's label
bl_options = {'REGISTER', 'UNDO'}
bl_description = "Add a yellow submarine" #tooltip

def execute(self, context):
'''
Function to process a click on the "Add Submarine" button
'''
bpy.ops.wm.append(directory="C:/Users/Youruser/Desktop/test_append/yellowsubmarine.blend/Scene/",
filename="submarine", link=False) #append submarine from .blend file
return{'FINISHED'}




def menu_item(self, context):
self.layout.operator(OBJECT_OT_addSubmarine.bl_idn ame, text="yellowsubmarine", icon="PLUGIN")


def register():
bpy.utils.register_module(__name__)
bpy.types.INFO_MT_mesh_add.append(menu_item)


def unregister():
bpy.utils.unregister_module(__name__)
bpy.types.INFO_MT_mesh_add.remove(menu_item)


if __name__ == "__main__":
register()