anchor.diff:             #:days-in-month
              #:timestamp-
              #:timestamp+
  -           #:duration
  -           #:decode-duration
  -           #:parse-duration
  -           #:format-duration
              #:timestamp-minimize-part
              #:timestamp-maximize-part
              #:with-decoded-timestamp
  
positive.code:     (when (minusp second)
        (decf day)
        (incf second +seconds-per-day+))
      (encode-duration :nsec nsec :sec second :day day)))
  
  (defun timestamp+ (time amount unit)
    (multiple-value-bind (nsec sec day)
  
negative.code:                     (* (or offset-minute 0) 60))
                   (%get-default-offset)))))
  
  (defun format-rfc3339-timestring (timestamp &key destination omit-date-part-p omit-time-part-p
                                    omit-timezone-part-p (use-zulu-p t))
    (format-timestring timestamp
  