def get_default_net_device():
with open('<STR_LIT>') as fh:<EOL><INDENT>for line in fh:<EOL><INDENT>iface, dest, _ = line.split(None, <NUM_LIT:2>)<EOL>if dest == '<STR_LIT>':<EOL><INDENT>return iface<EOL><DEDENT><DEDENT><DEDENT>return None<EOL>
Find the device where the default route is.