The board of directors of any school district of the state of Washington which now has, or hereafter shall have, funds in the capital projects fund of the district in the office of the county treasurer which in the judgment of said board are not required for the immediate necessities of the district, may invest and reinvest all, or any part, of such funds pursuant to RCW
35.39.030,
36.29.020,
36.29.022,
36.29.024,
39.59.020, *
39.59.030, and
43.84.080: PROVIDED, That nothing herein authorized, or the type and character of the securities thus specified, shall have in itself the effect of delaying any program of building for which said funds shall have been authorized. Said funds and said securities and the profit and interest thereon, and the proceeds thereof, shall be held by the county treasurer to the credit and benefit of the capital projects fund of the district in the county treasurer's office.