For the purpose of this chapter to bargain collectively is the performance of the mutual obligation of the employer and the representative of the employees to meet at reasonable times and confer in good faith with respect to all matters bargainable under the provisions of this chapter; but the failure or refusal of either party to agree to a proposal, or to change or withdraw a lawful proposal, or to make a concession shall not constitute, or be evidence direct or indirect, of a breach of this obligation. (Added 1969, No. 113, § 1.)