'Run dpctl (or ovs-ofctl) command on all switches.
Usage: dpctl command [arg1] [arg2] ...'

def do_dpctl(self, line):

    args = line.split()
    if (len(args) < 1):
        error('usage:    dpctl    command    [arg1]    [arg2]    ...\n')
        return
    for sw in self.mn.switches:
        output((((('***    ' + sw.name) + '    ') + ('-' * 72)) + '\n'))
        output(sw.dpctl(*args))
