def cli(env, volume_id, replicant_id):
    """Failback a block volume from the given replicant volume."""
    block_storage_manager = SoftLayer.BlockStorageManager(env.client)

    success = block_storage_manager.failback_from_replicant(
        volume_id,
        replicant_id
    )

    if success:
        click.echo("Failback from replicant is now in progress.")
    else:
        click.echo("Failback operation could not be initiated.")
Failback a block volume from the given replicant volume.