Exception when network connection is gone

[sphaero]

Exception in thread Thread-3:
Traceback (most recent call last):
  File "/usr/lib/python3.3/threading.py", line 637, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.3/threading.py", line 594, in run
    self._target(*self._args, **self._kwargs)
  File "/home/arnaud/Documents/sphaero/zmq-test/pyzyre/zbeacon.py", line 171, in __init__
    self.run()
  File "/home/arnaud/Documents/sphaero/zmq-test/pyzyre/zbeacon.py", line 262, in run
    self.send()
  File "/home/arnaud/Documents/sphaero/zmq-test/pyzyre/zbeacon.py", line 213, in send
    self._udp_sock.sendto(self.transmit, (self._dstAddr, self._port))
OSError: [Errno 101] Network is unreachable]