Переименование блока

(defun ru-block-rename (block_old_name block_new_name)
  (if (/= block_old_name block_new_name)
    ;;Переименование блока
    (progn
      (princ
        (strcat "
Переименовываю "
                block_old_name     " в "
                block_new_name     "
"
               ) ;_ end of strcat
      ) ;_ end of princ
      (if (and (/= block_old_name "")
               (/= block_new_name "")
               (tblobjname "block" block_old_name)
               (not (tblobjname "block" block_new_name)
               ) ;_ end of not
          ) ;_ end of and
        (ru-error-catch
          (function (lambda ()
                      (vla-put-name
                        (vla-item
                          (vla-get-blocks
                            (ru-obj-get-active-document)
                          ) ;_ end of vla-get-blocks
                          block_old_name
                        ) ;_ end of vla-item
                        block_new_name
                      ) ;_ end of vla-put-name
                    ) ;_ end of lambda
          ) ;_ end of function
          NIL
        ) ;_ end of ru-error-catch
      ) ;_ end of if
    ) ;_ end of progn
  ) ;_ end of if
) ;_ end of defun