anchor.diff:    "Get a list of all registered backends.
   
   See also: `enabled-backends'"
  -  (keys *backends*))
  +  *backends*)
   
   (defun enabled-backends ()
     "Get a list of all enabled backends.
  
positive.code: 
  (defun event-backends (event)
    "Get a list of backends that EVENT should be played on, either via the event's :backend key or via the `enabled-backends'."
    (or (ensure-list (or (event-value event :backends)
                         (event-value event :backend)))
        (enabled-backends)))
  
  ;;; backend management
  
negative.code: 
  (defun lookup-object-for-symbol (symbol)
    "Look up the object named by SYMBOL using `*dictionary-lookup-functions*'. Returns nil if no object was found."
    (dolist (func *dictionary-lookup-functions*)
      (when-let ((res (ignore-errors (funcall func symbol))))
        (return-from lookup-object-for-symbol res))))
  
  (defun task-nodes (task backend)
    "Get the list of nodes for TASK for the specified backend. If BACKEND is nil, get all of the resources for TASK regardless of backend."
  