'Fetch io counters from psutil and transform it to
dicts with the additional attributes defaulted'

def _get_net_io_counters(self):

    counters = psutil.net_io_counters(pernic=self.pernic)
    res = {}
    for (name, io) in counters.iteritems():
        res[name] = io._asdict()
        res[name].update({'tx_per_sec': 0, 'rx_per_sec': 0})
    return res
