Fix heartbeat + remove warnings

Domoticz.py

@@ -1,3 +1,5 @@
+"""Module simulating Domoticz"""
+#pylint: disable=invalid-name, missing-function-docstring, missing-class-docstring, redefined-outer-name
 from datetime import datetime
 
 Images = {}
@@ -17,7 +19,6 @@ class DzImage(object):
         self.__name = name[:-4]
 
     def Create(self):
-        global Images
         Images[self.__name] = ImageObj(self)
 
 ###################
@@ -33,7 +34,6 @@ class DeviceObj(object):
     __unit=None
     __switchtype=None
     __options=None
-    __image=None
     __used=None
 
     def __init__(self, Unit=None, Name=None, Type=None, TypeName=None, Subtype=None, Switchtype=None, Options=None, Image=None, Used=None):
@@ -81,7 +81,6 @@ class DzDevice(object):
         self.__data = kwargs
 
     def Create(self):
-        global Devices
         Devices[self.__data["Unit"]] = DeviceObj(**self.__data)
 
 ###################
@@ -152,6 +151,7 @@ def Error(message):
 
 def Heartbeat(duration):
     """Heartbeat"""
+    domo.Heartbeat(duration)
 
 def DomoticzImage(name):
     """Image"""