anchor.diff:  (defclass <rescue-env> (<fully-observable-env>)
     ((nav-graph :accessor nav-graph :initarg :nav-graph
                 :initform (required-initarg :map))
  -   (home-node :accessor home-node :initarg :home-node
  -              :initform (required-initarg :home-node))
  +   (home-nodes :accessor home-nodes :initarg :home-nodes
  +               :initform (required-initarg :home-nodes))
      (max-damage :accessor max-damage :initarg :max-damage
                  :initform 500)
      (invalid-action-cost :accessor invalid-action-cost :initarg :invalid-action-cost
                           :initform 2.0)))
   
   
  -(defmethod initialize-instance :around ((self <rescue-env>) &key home-node nav-graph)
  +(defmethod initialize-instance :around ((self <rescue-env>) &key home-nodes nav-graph)
     (call-next-method self
  -                    :home-node (find-node nav-graph home-node)
  +                    :home-nodes (mapcar (lambda (node)
  +                                          (find-node nav-graph node))
  +                                        home-nodes)
                       :nav-graph nav-graph))
   
   #||
  
positive.code: 			      (remove item (rs-objects state))))))))))
          (values new-state (rescue-reward env state action new-state)))))
  
  (defmethod sample-init ((env <rescue-env>))
    (let* ((graph (nav-graph env))
           ;; (node-1 (find-node graph 1))
           (node-2 (find-node graph 2))
           (node-3 (find-node graph 3)))
      (make-rescue-state
       :location (home-node env)
       :target-locations (list (home-node env))
       :objects (list (make-victim :v1 node-2 24)
                      (make-rubble :r1 node-3)))))
  
  
negative.code:                            '((1 2) (2 1)
                               (1 4) (4 1)
                               (2 3) (3 2)))
      :home-nodes '(1)))
  
  (defun load-rescue-env (file)
    (with-open-file (stream file :direction :input)
      (destructuring-bind (&key nav-graph home-nodes) (read stream)
        (make-instance '<rescue-env>
          :nav-graph (apply 'make-graph nav-graph)
          :home-nodes home-nodes))))
  
  (defun make-rescue-env-1 ()
    (load-rescue-env "rescue-scenario-01.lisp"))
  