docs: def RecreateInstanceDisks(r, instance, disks=None, nodes=None):
      """Recreate an instance's disks.
  
      @type instance: string
      @param instance: Instance name
      @type disks: list of int
      @param disks: List of disk indexes
      @type nodes: list of string
      @param nodes: New instance nodes, if relocation is desired
      @rtype: string
      @return: job id
      """
  
      body = {}
  
      if disks is not None:
          body["disks"] = disks
      if nodes is not None:
          body["nodes"] = nodes
  
      return r.request("post", "/2/instances/%s/recreate-disks" % instance,
                       content=body)