Update school buy logic

apps/payment/views.py

@@ -1,5 +1,6 @@
-import logging
+import arrow
 import json
+import logging
 
 from datetime import timedelta
 from urllib.parse import urlsplit
@@ -203,11 +204,11 @@ class PaymentwallCallbackView(View):
                             date_start = now()
                             date_end = school_payment.date_end
                         else:
-                            date_start = school_payment.date_end + timedelta(days=1)
-                            date_end = date_start + timedelta(days=30)
+                            date_start = arrow.get(school_payment.date_end).shift(days=1).datetime
+                            date_end = arrow.get(date_start).shift(months=1).datetime
                     else:
                         date_start = now()
-                        date_end = now() + timedelta(days=30)
+                        date_end = arrow.get(date_start).shift(months=1).datetime
                     payment.date_start = date_start
                     payment.date_end = date_end
             if product_type_name == 'course':