What would be the nicest way to code(in Python) a pie menu in Blender 2.79 or 2.8, that would have another menu as an addition to the standard 8 pie menu choices?

After playing with it for some time I found that this kind of works:

import bpy
# label is displayed at the center of the pie menu.
bl_label = "Select Mode"

def draw(self, context):
layout = self.layout
pie.separator()
pie.separator()
gap = pie.column()
gap.separator()
gap.separator()
gap.separator()
gap.separator()
gap.separator()
gap.separator()
gap.separator()

def register():
bpy.utils.register_class(VIEW3D_PIE_template)

def unregister():
bpy.utils.unregister_class(VIEW3D_PIE_template)

if __name__ == "__main__":
register()