Update CPU stats using SNMP.

def update_snmp(self):
        """Update CPU stats using SNMP."""

        # Init new stats
        stats = self.get_init_value()

        # Update stats using SNMP
        if self.short_system_name in ('windows', 'esxi'):
            # Windows or VMWare ESXi
            # You can find the CPU utilization of windows system by querying the oid
            # Give also the number of core (number of element in the table)
            try:
                cpu_stats = self.get_stats_snmp(snmp_oid=snmp_oid[self.short_system_name],
                                                bulk=True)
            except KeyError:
                self.reset()

            # Iter through CPU and compute the idle CPU stats
            stats['nb_log_core'] = 0
            stats['idle'] = 0
            for c in cpu_stats:
                if c.startswith('percent'):
                    stats['idle'] += float(cpu_stats['percent.3'])
                    stats['nb_log_core'] += 1
            if stats['nb_log_core'] > 0:
                stats['idle'] = stats['idle'] / stats['nb_log_core']
            stats['idle'] = 100 - stats['idle']
            stats['total'] = 100 - stats['idle']

        else:
            # Default behavor
            try:
                stats = self.get_stats_snmp(
                    snmp_oid=snmp_oid[self.short_system_name])
            except KeyError:
                stats = self.get_stats_snmp(
                    snmp_oid=snmp_oid['default'])

            if stats['idle'] == '':
                self.reset()
                return self.stats

            # Convert SNMP stats to float
            for key in iterkeys(stats):
                stats[key] = float(stats[key])
            stats['total'] = 100 - stats['idle']

        return stats