code: def unregister_listener(self, address, func):
          
          listeners = self.address_listeners[address]
          if listeners is None:
              return False
  
          if func in listeners:
              listeners.remove(func)
              return True
  
          return False
docs: Removes a listener function for a given address
  
          Remove the listener for the given address. Returns true if the listener
          was found and removed, false otherwise