'Deregisters an Amazon ECS container instance from the
specified cluster. This instance will no longer be available
to run tasks.
:type cluster: string
:param cluster: The short name or full Amazon Resource Name (ARN) of
the cluster that hosts the container instance you want to
deregister. If you do not specify a cluster, the default cluster is
assumed.
:type container_instance: string
:param container_instance: The container instance UUID or full Amazon
Resource Name (ARN) of the container instance you want to
deregister. The ARN contains the `arn:aws:ecs` namespace, followed
by the region of the container instance, the AWS account ID of the
container instance owner, the `container-instance` namespace, and
then the container instance UUID. For example, arn:aws:ecs: region
: aws_account_id :container-instance/ container_instance_UUID .
:type force: boolean
:param force: Force the deregistration of the container instance. You
can use the `force` parameter if you have several tasks running on
a container instance and you don\'t want to run `StopTask` for each
task before deregistering the container instance.'

def deregister_container_instance(self, container_instance, cluster=None, force=None):

    params = {'containerInstance': container_instance}
    if (cluster is not None):
        params['cluster'] = cluster
    if (force is not None):
        params['force'] = str(force).lower()
    return self._make_request(action='DeregisterContainerInstance', verb='POST', path='/', params=params)
