Update IP stats using the input method.

        Stats is dict

def update(self):
        """Update IP stats using the input method.

        Stats is dict
        """
        # Init new stats
        stats = self.get_init_value()

        if self.input_method == 'local' and not import_error_tag:
            # Update stats using the netifaces lib
            try:
                default_gw = netifaces.gateways()['default'][netifaces.AF_INET]
            except (KeyError, AttributeError) as e:
                logger.debug("Cannot grab the default gateway ({})".format(e))
            else:
                try:
                    stats['address'] = netifaces.ifaddresses(default_gw[1])[netifaces.AF_INET][0]['addr']
                    stats['mask'] = netifaces.ifaddresses(default_gw[1])[netifaces.AF_INET][0]['netmask']
                    stats['mask_cidr'] = self.ip_to_cidr(stats['mask'])
                    stats['gateway'] = netifaces.gateways()['default'][netifaces.AF_INET][0]
                    stats['public_address'] = self.public_address
                except (KeyError, AttributeError) as e:
                    logger.debug("Cannot grab IP information: {}".format(e))
        elif self.input_method == 'snmp':
            # Not implemented yet
            pass

        # Update the stats
        self.stats = stats

        return self.stats