Update the AMP

def update(self, process_list):
        """Update the AMP"""
        # Get the systemctl status
        logger.debug('{}: Update stats using systemctl {}'.format(self.NAME, self.get('systemctl_cmd')))
        try:
            res = check_output(self.get('systemctl_cmd').split())
        except (OSError, CalledProcessError) as e:
            logger.debug('{}: Error while executing systemctl ({})'.format(self.NAME, e))
        else:
            status = {}
            # For each line
            for r in to_ascii(res).split('\n')[1:-8]:
                # Split per space .*
                column = r.split()
                if len(column) > 3:
                    # load column
                    for c in range(1, 3):
                        try:
                            status[column[c]] += 1
                        except KeyError:
                            status[column[c]] = 1
            # Build the output (string) message
            output = 'Services\n'
            for k, v in iteritems(status):
                output += '{}: {}\n'.format(k, v)
            self.set_result(output, separator=' ')

        return self.result()