def gettunnel(self, n1num, n2num):
        key = self.tunnelkey(n1num, n2num)
        if key in self.tunnels.keys():
            return self.tunnels[key]
        else:
            return None
Return the GreTap between two nodes if it exists.
dataset/ETHPy150Open coreemu/core/daemon/core/broker.py/CoreBroker.gettunnel