How to assign a type annotation to a class in Custom Addons

Hi I’m running on windows 10 with blender 2.82

I keep getting these annotation type warnings which I understand are common but not breaking for addons that have compatibility 2.8 and 2.7, however, when trying to run blender in the background it becomes breaking.

Warning: class WM_OT_import_modal contains a property that should be an annotation!
c:\Users\Willard\Desktop\blender\2.82\scripts\addons\sketchfab_init_.py:1648
assign as a type annotation: WM_OT_import_modal.gltf_path
assign as a type annotation: WM_OT_import_modal.uid
You are using the latest version(1.3.1)
ERROR (wm.operator): c:\b\win64_cmake_vs2017\win64_cmake_vs2017\blender.git\source\blender\windowmanager\intern\wm_event_system.c:1486 wm_operator_invoke: invalid operator call ‘WM_OT_import_modal’

Below is the class in the addon throwing the error.

class ImportModalOperator(bpy.types.Operator):
    bl_idname = "wm.import_modal"
    bl_label = "Import glTF model into Sketchfab"ltf)
    bl_options = {'INTERNAL'}

    gltf_path = StringProperty()
    uid = StringProperty()

It would seem I just need to assign the properties: “gltf_path” and “uid” as type annotation to fix my error. But I can not conceive how to do this.

class ImportModalOperator(bpy.types.Operator):
    bl_idname = "wm.import_modal"
    bl_label = "Import glTF model into Sketchfab"ltf)
    bl_options = {'INTERNAL'}

    gltf_path: StringProperty()
    uid: StringProperty()

If you want to add properties to existing classes you will need to add to the __annotations__ dict directly.