def tearDown(self):
        self.sniffer.stop()
        del self.sniffer

        for node in list(self.nodes.values()):
            node.stop()
        del self.nodes

 def tearDown(self):
     for node in list(self.nodes.values()):
         node.stop()
     del self.nodes

 def tearDown(self):
     for node in list(self.nodes.values()):
         node.stop()
         node.destroy()
     self.simulator.stop()

 def tearDown(self):
     for node in self.nodes.itervalues():
         node.stop()
     del self.nodes