Flask-SMorest Upload Field Validation with OneOf Validator

from\u0020flask_smorest.fields\u0020import\u0020Upload\n\nclass\u0020UploadArgSchema(ArgSchema):\n\u0020\u0020file\u0020=\u0020Upload(\n\u0020\u0020\u0020\u0020description='待上传文件',\u0020required=True,\u0020error_messages={'required': '待上传文件不能为空'}\n\u0020\u0020)\n\nTo\u0020achieve\u0020this\u0020requirement,\u0020you\u0020can\u0020modify\u0020the\u0020UploadArgSchema\u0020class\u0020as\u0020follows:\n\npython\nfrom\u0020flask_smorest.fields\u0020import\u0020Upload\nfrom\u0020marshmallow\u0020import\u0020validate\n\nclass\u0020UploadArgSchema(ArgSchema):\n\u0020\u0020file\u0020=\u0020Upload(\n\u0020\u0020\u0020\u0020description='待上传文件',\u0020required=True,\u0020error_messages={'required': '待上传文件不能为空'},\n\u0020\u0020\u0020\u0020validate=validate.OneOf(['1', '2', '3'])\n\u0020\u0020)\n\n\nIn\u0020the\u0020above\u0020code,\u0020we\u0020added\u0020the\u0020validate\u0020argument\u0020to\u0020the\u0020Upload\u0020field\u0020and\u0020specified\u0020validate.OneOf(['1', '2', '3'])\u0020as\u0020the\u0020validator.\u0020This\u0020ensures\u0020that\u0020only\u0020the\u0020values\u0020'1', '2',\u0020or\u0020'3'\u0020are\u0020allowed\u0020for\u0020the\u0020file\u0020field.