Use OccupationSerializer for the Contacts API

webapp/models.py

@@ -195,7 +195,7 @@ class Occupation(models.Model):
     role = models.ForeignKey('Role', on_delete=models.SET_NULL, null=True)
 
     @staticmethod
-    def occupations_by_year(year):
+    def by_year(year):
         return Occupation.objects.filter(
             end_date__gte=timezone.datetime(year, 1, 1)).filter(
             start_date__lte=timezone.datetime(year, 12, 31))
@@ -219,14 +219,10 @@ class Official(models.Model):
     last_name = models.CharField(_('Last name'), max_length=150)
     email = models.EmailField(_('Email address'))
     phone_number = PhoneNumberField(_('Phone number'))
-    role_history = models.ManyToManyField('Occupation', blank=True)
-
-    @property
-    def current_roles(self):
-        return self.role_history.all().filter(end_date__gte=timezone.now())
+    role_history = models.ManyToManyField('Occupation', 'officials', blank=True)
 
     @staticmethod
-    def official_by_year(year):
+    def by_year(year):
         return Official.objects.filter(
             role_history__in=Occupation.occupations_by_year(year)).distinct()