Complex sentence: This license is often used for the purpose of self-promotion; for instance a cellist who played on a recorded song may obtain a mechanical license in order to distribute copies of the song to others as an example of his cello playing.
Split into simpler sentences: This license is often used for the purpose of self-promotion. For instance a cellist who played on a recorded song may obtain a mechanical license in order to distribute copies of the song to others as an example of his cello playing.