shading menu for with objects and without objects

shading.py

class PieRMB(Menu):
    bl_idname = "pie.shadingview"
    bl_label = "Viewport Shading "

    def draw(self, context):
        layout = self.layout

        obj = context.object
        pie = layout.menu_pie()

        scene = context.scene
        view = context.space_data
           
        #4 - LEFT
        f = pie.operator("wm.context_set_enum", icon='WIRE', text='Wires')
        f.data_path='space_data.viewport_shade'
        f.value = 'WIREFRAME'
        #6 - RIGHT
        pie.operator("object.hide_view_clear", text="Show Object")                
        
        #2 - BOTTOM
        box = pie.split().box().column()
        row = box.row()
        box.operator("OBJECT_OT_shade_smooth", text="Object Smooth")
        row = box.row()
        box.operator("OBJECT_OT_shade_flat", text="Object Flat")
        box.separator()
        box.operator("calculate.normal", text="Calculate Normals")
        box.separator()
        row = box.row()
        if obj:
            mesh = obj.data
            row.prop(mesh, "use_auto_smooth")
            row = box.row()
            row.prop(mesh, "auto_smooth_angle", text="Angle")
            box.separator()
        box.prop(view, "use_matcap")
        box.template_icon_view(view, "matcap_icon")
        
        #8 - TOP
        f = pie.operator("wm.context_set_enum", icon='SMOOTH', text='Rendered')
        f.data_path='space_data.viewport_shade'
        f.value = 'RENDERED'
        #7 - TOP - LEFT
        f = pie.operator("wm.context_set_enum", icon='SOLID', text='Solid')
        f.data_path='space_data.viewport_shade'
        f.value = 'SOLID' 
        #9 - TOP - RIGHT
        f = pie.operator("wm.context_set_enum", icon='MATERIAL', text='Material')
        f.data_path='space_data.viewport_shade'
        f.value = 'MATERIAL'
        #1 - BOTTOM - LEFT
        pie.operator("object.hide_view_set", text="Hide Object Selected").unselected=False
        #3 - BOTTOM - RIGHT
        pie.operator("object.hide_view_set", text="Hide Object Unselected").unselected=True