Add send_subscriber_agreement function

Author: Bono

xolphin/endpoint/request.py

@@ -44,8 +44,14 @@ def retry_dcv(self, id, domain, dcv_type, email=''):
             'email': email
         }))
 
+    def send_subscriber_agreement(self, id, email, language='nl'):
+        return Base(self.client.post('requests/{id}/sa'.format(id=id), {
+            'email': email,
+            'language': language
+        }))
+
     def schedule_validation_call(self, id, date_time):
         return Base(self.client.post('requests/%d/schedule-validation-call' % id, {
             'date': date_time.strftime('%Y-%m-%d'),
             'time': date_time.strftime('%H:%M')
-        }))
+        }))