Section 4547. Compromise and offers to compromise

Evidence  of  (a)
  furnishing, or offering or promising to furnish, or  (b)  accepting,  or
  offering   or   promising  to  accept,  any  valuable  consideration  in
  compromising or attempting to compromise a claim which is disputed as to
  either validity or amount of damages, shall be inadmissible as proof  of
  liability  for  or  invalidity  of  the  claim or the amount of damages.
  Evidence of any conduct or statement made during compromise negotiations
  shall also be inadmissible. The provisions of  this  section  shall  not
  require  the exclusion of any evidence, which is otherwise discoverable,
  solely  because  such  evidence  was  presented  during  the  course  of
  compromise  negotiations. Furthermore, the exclusion established by this
  section shall not limit the admissibility of such evidence  when  it  is
  offered  for  another  purpose,  such  as proving bias or prejudice of a
  witness, negating a contention of undue delay or proof of an  effort  to
  obstruct a criminal investigation or prosecution.