of non-Internal Revenue Service employees to returns and return information (a) In general Section 7602 is amended by adding at the end the following new subsection: (f) Limitation on access of persons other than Internal Revenue Service officers and employees The Secretary shall not, under the authority of section 6103(n), provide any books, papers, records, or other data obtained pursuant to this section to any person authorized under section 6103(n), except when such person requires such information for the sole purpose of providing expert evaluation and assistance to the Internal Revenue Service. No person other than an officer or employee of the Internal Revenue Service or the Office of Chief Counsel may, on behalf of the Secretary, question a witness under oath whose testimony was obtained pursuant to this section. . (b) Effective date (1) In general Except as provided in paragraph (2), the amendment made by this section shall take effect on the date of the enactment of this Act. (2) Application to contracts in effect The amendment made by this section shall apply to any contract in effect under section 6103(n) of the Internal Revenue Code of 1986, pursuant to temporary Treasury Regulation section 301.7602–1T proposed in Internal Revenue Bulletin 2014–28, Treasury Regulation section 301.7602–1(b)(3), or any similar or successor regulation, that is in effect on the date of the enactment of this Act.