'Report on node shell status'

def do_status(self, _line):

    nodes = (self.mn.hosts + self.mn.switches)
    for node in nodes:
        node.shell.poll()
    exited = [node for node in nodes if (node.shell.returncode is not None)]
    if exited:
        for node in exited:
            output(('%s    has    exited    with    code    %d\n' % (node, node.shell.returncode)))
    else:
        output('All    nodes    are    still    running.\n')
