CynaCons

import dbus
import time

bus = dbus.SystemBus()

#Build a proxy for the Adapter
adapter_proxy = bus.get_object("org.bluez", "/org/bluez/hci0")

#Call the method StartDiscovery from the adapter api then StopDiscovery
adapter_proxy.StartDiscovery(dbus_interface="org.bluez.Adapter1")

CynaCons

import dbus
import time

"""
This gist will do the following things : 
    1. Setup GLib and a MainLoop. MainLoop is required to receive signals from the dbus
    
    2. Define a simple callback function that will be associated to the signal "Properties Changed" for a specific object (Characteristic).
       The callback function will be called when the characteristic value is updated or it's property changed.