Portrait of A. Kasyanov. 1907 Valentin Serov (1865-1911)

The picture has something of this: people, portrait, man, mustache, facial hair, wear, lid, leader, menswear, music, outfit, retro, neckwear, vest, cravat, facial expression.
Perhaps it’s a painting of a man in a black suit and tie sitting in a chair with his arm resting on a piece of paper in his other hand.