§ 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.