Given a dict with the structure of a response from boto3.ec2.describe_instances(...),
        find the public/private ips.
        :param reservations:
        :return:

def _process_reservations(self, reservations):
        """
        Given a dict with the structure of a response from boto3.ec2.describe_instances(...),
        find the public/private ips.
        :param reservations:
        :return:
        """

        reservations = reservations['Reservations']

        private_ip_addresses = []
        private_hostnames = []
        public_ips = []
        public_hostnames = []
        for reservation in reservations:
            for instance in reservation['Instances']:
                private_ip_addresses.append(instance['PrivateIpAddress'])
                private_hostnames.append(instance['PrivateDnsName'])

                if 'PublicIpAddress' in instance:
                    public_ips.append(instance['PublicIpAddress'])
                elif not self.remove_nones:
                    public_ips.append(None)

                if ('PublicDnsName' in instance) & (not self.remove_nones):
                    public_hostnames.append(instance['PublicDnsName'])
                elif not self.remove_nones:
                    public_hostnames.append(None)

        return {
            'private': {
                'ips': private_ip_addresses,
                'hostnames': private_hostnames
            },
            'public': {
                'ips': public_ips,
                'hostnames': public_hostnames
            },
            'reservations': reservations
        }