improve: introduce isort for linting Python imports (#1983)

api/controllers/files/__init__.py

@@ -1,6 +1,5 @@
 # -*- coding:utf-8 -*-
 from flask import Blueprint
-
 from libs.external_api import ExternalApi
 
 bp = Blueprint('files', __name__)

api/controllers/files/image_preview.py

@@ -1,12 +1,11 @@
-from flask import request, Response
-from flask_restful import Resource
-from werkzeug.exceptions import NotFound
-
 import services
 from controllers.files import api
+from flask import Response, request
+from flask_restful import Resource
 from libs.exception import BaseHTTPException
-from services.file_service import FileService
 from services.account_service import TenantService
+from services.file_service import FileService
+from werkzeug.exceptions import NotFound
 
 
 class ImagePreviewApi(Resource):