Section 190.45. Grand jury; waiver of immunity

1.    A  waiver  of  immunity  is a written instrument subscribed by a
  person who is  or  is  about  to  become  a  witness  in  a  grand  jury
  proceeding,   stipulating   that   he   waives   his  privilege  against
  self-incrimination and any possible or prospective immunity to which  he
  would otherwise become entitled, pursuant to section 190.40, as a result
  of giving evidence in such proceeding.
    2.  A waiver of immunity is not effective unless and until it is sworn
  to  before  the  grand  jury  conducting  the  proceeding  in  which the
  subscriber has been called as a witness.
    3.  A person who is called by the people as a witness in a grand  jury
  proceeding and requested by the district attorney to subscribe and swear
  to  a  waiver  of  immunity before giving evidence has a right to confer
  with counsel before deciding whether he will comply with  such  request,
  and, if he desires to avail himself of such right, he must be accorded a
  reasonable  time  in  which  to  obtain and confer with counsel for such
  purpose.  The district attorney must inform  the  witness  of  all  such
  rights before obtaining his execution of such a waiver of immunity.  Any
  waiver  obtained,  subscribed or sworn to in violation of the provisions
  of this subdivision is invalid and ineffective.
    4.  If a grand jury witness subscribes  and  swears  to  a  waiver  of
  immunity  upon  a  written agreement with the district attorney that the
  interrogation will be limited to certain specified subjects, matters  or
  areas  of  conduct, and if after the commencement of his testimony he is
  interrogated and testifies concerning another subject, matter or area of
  conduct not included in such written  agreement,  he  receives  immunity
  with  respect to any further testimony which he may give concerning such
  other subject, matter or area of conduct and the waiver of  immunity  is
  to that extent ineffective.