diff --git a/libs/lib/xaal/lib/devices.py b/libs/lib/xaal/lib/devices.py
index 4d4ff1a9fb8aa9fccd2cbd9884b466f592736470..28cd320d8e291bf0df724e9fcabdece7e31d1dc7 100644
--- a/libs/lib/xaal/lib/devices.py
+++ b/libs/lib/xaal/lib/devices.py
@@ -28,7 +28,7 @@ from . import config
 from . import tools
 from . import bindings
 from .exceptions import DeviceError
-from .types import UUIDT, DeviceT, EngineT, AsyncEngineT
+from .types import DeviceT, EngineT, AsyncEngineT
 
 
 logger = logging.getLogger(__name__)
@@ -39,7 +39,7 @@ class Attribute(object):
     def __init__(self, name, dev: Optional[DeviceT] = None, default: Any = None):
         self.name = name
         self.default = default
-        self.device = dev
+        self.device: Optional[Device] = dev
         self.__value = default
 
     @property
@@ -104,7 +104,7 @@ class Device(object):
     def __init__(
         self,
         dev_type: str,
-        addr: Optional[UUIDT] = None,
+        addr: Optional[bindings.UUID] = None,
         engine: Union[EngineT, AsyncEngineT, None] = None,
     ):
 
@@ -156,11 +156,11 @@ class Device(object):
             self.__version = None
 
     @property
-    def address(self):
+    def address(self) -> Optional[bindings.UUID]:
         return self.__address
 
     @address.setter
-    def address(self, value: Optional[UUIDT]):
+    def address(self, value: Optional[bindings.UUID]):
         if value is None:
             self.__address = None
             return
@@ -169,60 +169,60 @@ class Device(object):
         self.__address = value
 
     @property
-    def url(self):
+    def url(self) -> Optional[bindings.URL]:
         return self.__url
 
     @url.setter
-    def url(self, value):
+    def url(self, value: Optional[str]):
         if value is None:
             self.__url = None
         else:
             self.__url = bindings.URL(value)
 
     # attributes
-    def new_attribute(self, name, default=None):
+    def new_attribute(self, name: str, default: Any = None):
         attr = Attribute(name,self,default)
         self.add_attribute(attr)
         return attr
 
-    def add_attribute(self, attr):
+    def add_attribute(self, attr: Attribute):
         if attr:
             self.__attributes.append(attr)
             attr.device = self
 
-    def del_attribute(self, attr):
+    def del_attribute(self, attr: Attribute):
         if attr:
             attr.device = None
             self.__attributes.remove(attr)
 
-    def get_attribute(self, name):
+    def get_attribute(self, name: str) -> Optional[Attribute]:
         for attr in self.__attributes:
             if attr.name == name:
                 return attr
         return None
 
     @property
-    def attributes(self):
+    def attributes(self) -> Attributes:
         return self.__attributes
 
     @attributes.setter
-    def attributes(self, values):
+    def attributes(self, values: Attributes):
         if isinstance(values,Attributes):
             self.__attributes = values
         else:
             raise DeviceError("Invalid attributes list, use class Attributes)")
 
-    def add_method(self, name, func):
+    def add_method(self, name: str, func: Any):
         self.methods.update({name:func})
 
-    def get_methods(self):
+    def get_methods(self) -> dict:
         return self.methods
 
     def update_alive(self):
         """ update the alive timimg"""
         self.next_alive = time.time() + self.alive_period
 
-    def get_timeout(self):
+    def get_timeout(self) -> int:
         """ return Alive timeout used for isAlive msg"""
         return 2 * self.alive_period
 
@@ -313,7 +313,7 @@ class Device(object):
                 result.update({attr.name: attr.value})
         return result
 
-    def send_notification(self, notification, body={}):
+    def send_notification(self, notification:str, body:dict={}):
         """ queue an notification, this is just a method helper """
         if self.engine:
             self.engine.send_notification(self,notification,body)