if defining `defun-prompt-regexp' is not sufficient to handle the mode's
needs.
-The function should go to the line on which the current defun starts,
-and return non-nil, or should return nil if it can't find the beginning.")
+The function (of no args) should go to the line on which the current
+defun starts, and return non-nil, or should return nil if it can't
+find the beginning.")
(defun beginning-of-defun (&optional arg)
"Move backward to the beginning of a defun.