Any person may be compelled to testify and produce books and writings at the trial or hearing of any person charged with violating any provision of sections 780 or 781 even though such testimony or evidence may incriminate him. A person shall not be prosecuted for any act concerning which he is compelled so to testify or produce evidence, except for perjury committed in so testifying.
(Enacted by Stats. 1935, Ch. 145.)