diff --git a/smash/web/models/mail_template.py b/smash/web/models/mail_template.py
index a7a83820df8bd24528f4e6036607727bdae6d261..1b04cf2b32a6ef37d8779995246f467a22e6e8d4 100644
--- a/smash/web/models/mail_template.py
+++ b/smash/web/models/mail_template.py
@@ -193,7 +193,8 @@ class MailTemplate(models.Model):
                 locale_name = self.language.windows_locale_name
         return locale_name
 
-    def get_generic_replacements(self, worker):
+    @staticmethod
+    def get_generic_replacements(worker):
         current_datetime = datetime.datetime.now()
         return {
             "##DATE_FULL##": current_datetime.strftime(DATE_FORMAT_FULL).decode(date_format_encoding()),
@@ -201,7 +202,8 @@ class MailTemplate(models.Model):
             "##WORKER##": unicode(worker)
         }
 
-    def get_appointment_replacements(self, appointment):
+    @staticmethod
+    def get_appointment_replacements(appointment):
         if appointment is None:
             return {}
 
@@ -236,7 +238,8 @@ class MailTemplate(models.Model):
             "##A_TYPES##": ", ".join([a.description for a in appointment.appointment_types.all()])
         }
 
-    def get_visit_replacements(self, visit):
+    @staticmethod
+    def get_visit_replacements(visit):
         if visit is not None:
             return {
                 "##V_DATE_START_FULL##": visit.datetime_begin.strftime(DATETIME_FORMAT).decode(date_format_encoding()),
@@ -247,7 +250,8 @@ class MailTemplate(models.Model):
             }
         return {}
 
-    def get_subject_replacements(self, study_subject):
+    @staticmethod
+    def get_subject_replacements(study_subject):
         if study_subject is not None:
             if study_subject.subject.date_born is not None:
                 date_born = study_subject.subject.date_born.strftime(DATE_FORMAT_SHORT).decode(date_format_encoding())
@@ -279,7 +283,8 @@ class MailTemplate(models.Model):
             }
         return {}
 
-    def get_voucher_replacements(self, voucher):
+    @staticmethod
+    def get_voucher_replacements(voucher):
         if voucher is not None:
             return {
                 "##C_NUMBER##": voucher.number,