_MMD_SHAPE vertex group not updated

[Hogarth-MMD]

The _MMD_SHAPE vertex group is not updated after someone creates a new shape key in Blender. This causes the shape key to be exported incorrectly. I made a bug fix for this:
Googleが翻訳します：
誰かがBlenderの新しいシェイプキーを作成した後_MMD_SHAPE頂点グループは更新されません。これは、シェイプキーが誤ってエクスポートされます。私はこのためにバグ修正を行いました。

import bpy

active = bpy.context.active_object

# deletes the _MMD_SHAPE vertex group. An essential bug fix for exporting shape keys which were created in Blender.
if '_MMD_SHAPE' in active.vertex_groups.keys():
    active.vertex_groups.remove(active.vertex_groups['_MMD_SHAPE'])