anchor.diff:                 nick
                  (describe-time-left expire-time))))))
   
  +(defun env-has-lease-p (module env-name)
  +  (find env-name (leases-of module)
  +        :key #'second
  +        :test #'string-equal))
  +
   (defun release-lease (module env-name nick)
     (cond
       ((not (member env-name (environments-of module) :test #'string-equal))
  
positive.code:          (send "~env                                    - list known environments")
           (send "~env <envname>                          - display environment info")
           (send "~env <envname> take <time> [<activity>] - lease the environment")
           (send "~env <envname> release                  - release your lease on environment")
           (send "~env <envname> add                      - add a new environment")
           (send "~env <envname> remove                   - remove an environment")
  
negative.code:            (reply-to message (query-leases module (first args) (leases-of module)))
             (reply-to message "Can't find environment ~a" env-name)))
        ((string-equal subcmd "take")
         (let ((lease (env-has-lease-p module env-name)))
           (if lease
             (reply-to message "~a is being leased by ~a for ~a.  You may share or steal the environment.")
             (reply-to message (create-lease module env-name (source message)
                                             (third args)
                                             (join-string #\space (cdddr args)))))))
        ((string-equal subcmd "share")
         (reply-to message (create-lease module env-name (source message)
                                         (third args)
                                         (join-string #\space (cdddr args)))))
        ((string-equal subcmd "steal")
         (remove-all-env-leases module env-name)
         (reply-to message (create-lease module env-name (source message)
                                         (third args)
                                         (join-string #\space (cdddr args)))))
  
        ((string-equal subcmd "release")
         (reply-to message (release-lease module env-name (source message))))
        ((string-equal subcmd "status")
  