diff --git a/helper.py b/helper.py
index d1a5dd4..65a5155 100644
--- a/helper.py
+++ b/helper.py
@@ -1,5 +1,8 @@
 import logging
 
+import parsedatetime
+
+from datetime import datetime
 from stripe_utils import StripeUtils
 
 
@@ -64,3 +67,21 @@ def calculate_charges(specification, data):
                     feature_detail['unit']['value']
             )
     return one_time_charge, recurring_charge
+
+
+def is_order_valid(order_timestamp, renewal_period):
+    """
+    Sample Code Usage
+
+    >> current_datetime, status = cal.parse('Now')
+    >> current_datetime = datetime(*current_datetime[:6])
+
+    >> print('Is order valid: ', is_order_valid(current_datetime, '1 month'))
+    >> True
+    """
+    cal = parsedatetime.Calendar()
+
+    renewal_datetime, status = cal.parse(renewal_period)
+    renewal_datetime = datetime(*renewal_datetime[:6])
+
+    return order_timestamp <= renewal_datetime
diff --git a/requirements.txt b/requirements.txt
index cb4f2a8..0f5d0d2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
+done
 stripe
 flask
 Flask-RESTful