They were also briefly lovers. Kochno wrote the libretto of Stravinsky's Mavra (1921), George Auric's Les Fâcheux (1924), Henri Sauguet's La Chatte (1927),  and of Sergei Prokofiev's ballet score The Prodigal Son (1929).
This passage describes Kochno's work as a librettist, specifically his collaborations with composers like Stravinsky, Auric, Sauguet, and Prokofiev.