(defun alist-to-hash-table (alist
                            &key (test 'eql)
                            &aux (hash-table (make-hash-table :test test)))
  (loop :for (key . value) :in alist
        :do (setf (gethash key hash-table) value))
  hash-table)

(defun hash-table-to-alist (hash-table)
  (let ((result '()))
    (maphash (lambda (key val)
	       (push (cons key val) result))
	     hash-table)
    result))

(def-serialize-method ((object hash-table) transaction-log) (id log-stream)
  (serialize `(alist-to-hash-table ,(hash-table-to-alist object)
				   :test ,(hash-table-test object))
	     transaction-log))