'Attaches volume to node.
@inherits :class:`NodeDriver.attach_volume`
:keyword device: device path allocated for this attached volume
:type device: ``str`` between /dev/xvdb to xvdz,
if empty, allocated by the system
:keyword ex_delete_with_instance: if to delete this volume when the
instance is deleted.
:type ex_delete_with_instance: ``bool``'

def attach_volume(self, node, volume, device=None, ex_delete_with_instance=None):

    params = {'Action': 'AttachDisk', 'InstanceId': node.id, 'DiskId': volume.id}
    if device:
        params['Device'] = device
    if ex_delete_with_instance:
        params['DeleteWithInstance'] = str(bool(ex_delete_with_instance)).lower()
    resp = self.connection.request(self.path, params)
    return resp.success()
