How to return specific value according to each request parameter

[wangxbwang]

for example ,when get a post parameter , if have a validate error, return a responce value 。not just a 422 error，Unprocessable Entity 。need
when name error，return {“value”: "Name","error":"lenth C5" }
when userName error，return {“value”: userName ","error":"lenth C5" }
when contact error，return {“value”: "contact ","error":"not exit" }
class AdminUserReRequestSchemaSchema(Schema):
Name = fields.Str(required=True,
validate= validate.Length(min=5),
error_messages={"required": {"message": "True required", "code": 400}},
description="用户名")
userName = fields.Str(required=True,
validate= validate.Length(min=5),
description="用户登录名称")
contact = fields.Str(required=True,description="联系方式")
limit = fields.Int(required=True,description="API type of awesome API", )

class UserRegisterAPI(MethodResource, Resource):
@doc(description='UserRegister. ', tags=['UserRegister'])
@use_kwargs(AdminUserReRequestSchemaSchema, location=('json'))
@marshal_with(AdminUserReResponseSchema,description = "fdfafafasfasd",apply ="") # marshalling
# @marshal_with( AdminUserReResponse2Schema)
def post(self, col,**kwargs):
return result,200