shall be used to provide, obtain, or arrange on behalf of a homeowner, legal representation involving or for the purposes of civil litigation. 4. Incremental housing choice voucher assistance (a) Authorization of appropriations There is authorized to be appropriated for each of fiscal years 2018 through 2022 such sums as may be necessary to provide in each such fiscal year 20,000 incremental vouchers for rental assistance under section 8(o) of the United States Housing Act of 1937 ( 42 U.S.C. 1437f(o) ). (b) Eligible public housing agencies Any amounts appropriated pursuant to this section shall be used by the Secretary of Housing and Urban Development only to provide additional amounts for rental assistance vouchers for public housing agencies that administer 10,000 or more vouchers for rental assistance under such section 8(o).