'Update the AMP'

def update(self, process_list):

    logger.debug('{}:    Update    stats    using    systemctl    {}'.format(self.NAME, self.get('systemctl_cmd')))
    try:
        res = check_output(self.get('systemctl_cmd').split())
    except OSError as e:
        logger.debug('{}:    Error    while    executing    systemctl    ({})'.format(self.NAME, e))
    else:
        status = {}
        for r in to_ascii(res).split('\n')[1:(-8)]:
            l = r.split()
            if (len(l) > 3):
                for c in range(1, 3):
                    try:
                        status[l[c]] += 1
                    except KeyError:
                        status[l[c]] = 1
        output = 'Services\n'
        for (k, v) in iteritems(status):
            output += '{}:    {}\n'.format(k, v)
        self.set_result(output, separator='    ')
    return self.result()
