This is a great movie / musical.
But might be difficult to find. It features barbershop music from the late 30's and early 40's. One notably is the SPEBSQSA (Society For the Preservation and Encouragement of Barbershop quartet singing in America, founded in 1938) Our 1940 International champions "Flat Foot Four" featured singing "Shine" on this work. It is highly worth the listen. If one desires to hear how acapella singing was done in the old days, this is clearly one way to go.
For more information about barbershop singing, contact your local library or the Barbershop Harmony Society, Headquartered in Nashville, Tenn.