Query EC2's DescribeAccountAttributes API action and
        update the network interface limit, as needed. Updates ``self.limits``.

        More info on the network interface limit, from the docs:
        'This limit is the greater of either the default limit (350) or your
        On-Demand Instance limit multiplied by 5.
        The default limit for On-Demand Instances is 20.'

def _update_limits_from_api(self):
        """
        Query EC2's DescribeAccountAttributes API action and
        update the network interface limit, as needed. Updates ``self.limits``.

        More info on the network interface limit, from the docs:
        'This limit is the greater of either the default limit (350) or your
        On-Demand Instance limit multiplied by 5.
        The default limit for On-Demand Instances is 20.'
        """
        self.connect()
        self.connect_resource()
        logger.info("Querying EC2 DescribeAccountAttributes for limits")
        attribs = self.conn.describe_account_attributes()
        for attrib in attribs['AccountAttributes']:
            if attrib['AttributeName'] == 'max-instances':
                val = attrib['AttributeValues'][0]['AttributeValue']
                if int(val) * 5 > DEFAULT_ENI_LIMIT:
                    limit_name = 'Network interfaces per Region'
                    self.limits[limit_name]._set_api_limit(int(val) * 5)
        logger.debug("Done setting limits from API")