Retrieve all the EC2 ramdisks available on your account.
        Constructs a filter to allow the processing to happen server side.

        :type ramdisk_ids: list
        :param ramdisk_ids: A list of strings with the image IDs wanted

        :type owners: list
        :param owners: A list of owner IDs

        :rtype: list
        :return: A list of :class:`boto.ec2.image.Image`

def get_all_ramdisks(self, ramdisk_ids=None, owners=None):
        """
        Retrieve all the EC2 ramdisks available on your account.
        Constructs a filter to allow the processing to happen server side.

        :type ramdisk_ids: list
        :param ramdisk_ids: A list of strings with the image IDs wanted

        :type owners: list
        :param owners: A list of owner IDs

        :rtype: list
        :return: A list of :class:`boto.ec2.image.Image`
        """
        params = {}
        if ramdisk_ids:
            self.build_list_params(params, ramdisk_ids, 'ImageId')
        if owners:
            self.build_list_params(params, owners, 'Owner')
        filter = {'image-type' : 'ramdisk'}
        self.build_filter_params(params, filter)
        return self.get_list('DescribeImages', params,
                             [('item', Image)], verb='POST')