diff --git a/server/src/uds/REST/methods/accountsusage.py b/server/src/uds/REST/methods/accountsusage.py
index 981cc5f4..75d0c671 100644
--- a/server/src/uds/REST/methods/accountsusage.py
+++ b/server/src/uds/REST/methods/accountsusage.py
@@ -53,7 +53,7 @@ class AccountsUsage(DetailHandler):  # pylint: disable=too-many-public-methods
     """
 
     @staticmethod
-    def usageToDict(item: 'AccountUsage', perm):
+    def usageToDict(item: 'AccountUsage', perm: int) -> typing.Dict[str, typing.Any]:
         """
         Convert an account usage to a dictionary
         :param item: Account usage item (db)
diff --git a/server/src/uds/REST/methods/authenticators.py b/server/src/uds/REST/methods/authenticators.py
index 945578f5..f0b221fc 100644
--- a/server/src/uds/REST/methods/authenticators.py
+++ b/server/src/uds/REST/methods/authenticators.py
@@ -97,7 +97,7 @@ class Authenticators(ModelHandler):
         except Exception:
             raise NotFound('type not found')
 
-    def item_as_dict(self, item: Authenticator):
+    def item_as_dict(self, item: Authenticator) -> typing.Dict[str, typing.Any]:
         type_ = item.getType()
         return {
             'numeric_id': item.id,
diff --git a/server/src/uds/REST/methods/calendarrules.py b/server/src/uds/REST/methods/calendarrules.py
index 4b3ed047..4441ef30 100644
--- a/server/src/uds/REST/methods/calendarrules.py
+++ b/server/src/uds/REST/methods/calendarrules.py
@@ -30,8 +30,9 @@
 """
 @author: Adolfo Gómez, dkmaster at dkmon dot com
 """
-import logging
 import datetime
+import logging
+import typing
 
 from django.utils.translation import ugettext as _
 from django.db import IntegrityError
@@ -45,6 +46,9 @@ from uds.core.util.model import processUuid
 from uds.REST.model import DetailHandler
 from uds.REST import RequestError
 
+# Not imported at runtime, just for type checking
+if typing.TYPE_CHECKING:
+    from uds.models import Calendar
 
 logger = logging.getLogger(__name__)
 
@@ -55,7 +59,7 @@ class CalendarRules(DetailHandler):  # pylint: disable=too-many-public-methods
     """
 
     @staticmethod
-    def ruleToDict(item, perm):
+    def ruleToDict(item: CalendarRule, perm: int):
         """
         Convert a calRule db item to a dict for a rest response
         :param item: Rule item (db)
@@ -76,7 +80,7 @@ class CalendarRules(DetailHandler):  # pylint: disable=too-many-public-methods
 
         return retVal
 
-    def getItems(self, parent, item):
+    def getItems(self, parent: 'Calendar', item: typing.Optional[str]):
         # Check what kind of access do we have to parent provider
         perm = permissions.getEffectivePermission(self._user, parent)
         try:
@@ -89,7 +93,7 @@ class CalendarRules(DetailHandler):  # pylint: disable=too-many-public-methods
             logger.exception('itemId %s', item)
             self.invalidItemException()
 
-    def getFields(self, parent):
+    def getFields(self, parent: 'Calendar') -> typing.List[typing.Any]:
         return [
             {'name': {'title': _('Rule name')}},
             {'start': {'title': _('Starts'), 'type': 'datetime'}},
@@ -100,7 +104,7 @@ class CalendarRules(DetailHandler):  # pylint: disable=too-many-public-methods
             {'comments': {'title': _('Comments')}},
         ]
 
-    def saveItem(self, parent, item):
+    def saveItem(self, parent: 'Calendar', item: typing.Optional[str]) -> None:
         # Extract item db fields
         # We need this fields for all
         logger.debug('Saving rule %s / %s', parent, item)
@@ -114,7 +118,7 @@ class CalendarRules(DetailHandler):  # pylint: disable=too-many-public-methods
         if fields['end'] is not None:
             fields['end'] = datetime.datetime.fromtimestamp(fields['end'])
 
-        calRule = None
+        calRule: CalendarRule
         try:
             if item is None:  # Create new
                 calRule = parent.rules.create(**fields)
@@ -132,7 +136,7 @@ class CalendarRules(DetailHandler):  # pylint: disable=too-many-public-methods
 
         return self.getItems(parent, calRule.uuid)
 
-    def deleteItem(self, parent, item):
+    def deleteItem(self, parent: 'Calendar', item: str) -> None:
         logger.debug('Deleting rule %s from %s', item, parent)
         try:
             calRule = parent.rules.get(uuid=processUuid(item))
@@ -143,9 +147,7 @@ class CalendarRules(DetailHandler):  # pylint: disable=too-many-public-methods
             logger.exception('Exception')
             self.invalidItemException()
 
-        return 'deleted'
-
-    def getTitle(self, parent):
+    def getTitle(self, parent: 'Calendar') -> str:
         try:
             return _('Rules of {0}').format(parent.name)
         except Exception:
diff --git a/server/src/uds/REST/methods/calendars.py b/server/src/uds/REST/methods/calendars.py
index 510af803..dd82090a 100644
--- a/server/src/uds/REST/methods/calendars.py
+++ b/server/src/uds/REST/methods/calendars.py
@@ -31,6 +31,7 @@
 @itemor: Adolfo Gómez, dkmaster at dkmon dot com
 """
 import logging
+import typing
 
 from django.utils.translation import ugettext_lazy as _
 from uds.models import Calendar
@@ -62,7 +63,7 @@ class Calendars(ModelHandler):
         {'tags': {'title': _('tags'), 'visible': False}},
     ]
 
-    def item_as_dict(self, item):
+    def item_as_dict(self, item: Calendar) -> typing.Dict[str, typing.Any]:
         return {
             'id': item.uuid,
             'name': item.name,
@@ -72,5 +73,5 @@ class Calendars(ModelHandler):
             'permission': permissions.getEffectivePermission(self._user, item)
         }
 
-    def getGui(self, type_):
+    def getGui(self, type_: str) -> typing.List[typing.Any]:
         return self.addDefaultFields([], ['name', 'comments', 'tags'])
diff --git a/server/src/uds/models/calendar.py b/server/src/uds/models/calendar.py
index c58cf21d..2cc86cfd 100644
--- a/server/src/uds/models/calendar.py
+++ b/server/src/uds/models/calendar.py
@@ -30,6 +30,7 @@
 .. moduleauthor:: Adolfo Gómez, dkmaster at dkmon dot com
 """
 import logging
+import typing
 
 from django.db import models
 from .uuid_model import UUIDModel
@@ -39,12 +40,20 @@ from .tag import TaggingMixin
 logger = logging.getLogger(__name__)
 
 
+# Not imported at runtime, just for type checking
+if typing.TYPE_CHECKING:
+    from uds.models import CalendarRule, CalendarAccess, CalendarAction
+
+
 class Calendar(UUIDModel, TaggingMixin):
 
     name = models.CharField(max_length=128, default='')
     comments = models.CharField(max_length=256, default='')
     modified = models.DateTimeField(auto_now=True)
 
+    # Sobmodels
+    rules: CalendarRule
+
     class Meta:
         """
         Meta class to declare db table
diff --git a/server/src/uds/models/calendar_access.py b/server/src/uds/models/calendar_access.py
index c33b5179..ccbe147f 100644
--- a/server/src/uds/models/calendar_access.py
+++ b/server/src/uds/models/calendar_access.py
@@ -47,8 +47,8 @@ logger = logging.getLogger(__name__)
 
 
 class CalendarAccess(UUIDModel):
-    calendar = models.ForeignKey(Calendar, on_delete=models.CASCADE)
-    service_pool = models.ForeignKey(ServicePool, related_name='calendarAccess', on_delete=models.CASCADE)
+    calendar: Calendar = models.ForeignKey(Calendar, on_delete=models.CASCADE)
+    service_pool: ServicePool = models.ForeignKey(ServicePool, related_name='calendarAccess', on_delete=models.CASCADE)
     access = models.CharField(max_length=8, default=states.action.DENY)
     priority = models.IntegerField(default=0, db_index=True)
 
diff --git a/server/src/uds/models/calendar_action.py b/server/src/uds/models/calendar_action.py
index beb4fc57..dc4114eb 100644
--- a/server/src/uds/models/calendar_action.py
+++ b/server/src/uds/models/calendar_action.py
@@ -76,8 +76,8 @@ CALENDAR_ACTION_DICT: typing.Dict[str, typing.Dict] = {c['id']: c for c in (
 
 
 class CalendarAction(UUIDModel):
-    calendar = models.ForeignKey(Calendar, on_delete=models.CASCADE)
-    service_pool = models.ForeignKey(ServicePool, on_delete=models.CASCADE)
+    calendar: Calendar = models.ForeignKey(Calendar, on_delete=models.CASCADE)
+    service_pool: ServicePool = models.ForeignKey(ServicePool, on_delete=models.CASCADE)
     action = models.CharField(max_length=64, default='')
     at_start = models.BooleanField(default=False)  # If false, action is done at end of event
     events_offset = models.IntegerField(default=0)  # In minutes
diff --git a/server/src/uds/models/calendar_rule.py b/server/src/uds/models/calendar_rule.py
index 92ba7722..6894d534 100644
--- a/server/src/uds/models/calendar_rule.py
+++ b/server/src/uds/models/calendar_rule.py
@@ -99,7 +99,7 @@ class CalendarRule(UUIDModel):
     duration = models.IntegerField(default=0)  # Duration in minutes
     duration_unit = models.CharField(choices=dunits, default='MINUTES', max_length=32)
 
-    calendar = models.ForeignKey(Calendar, related_name='rules', on_delete=models.CASCADE)
+    calendar: Calendar = models.ForeignKey(Calendar, related_name='rules', on_delete=models.CASCADE)
 
     class Meta:
         """