Before class, convening music is played. Different trainings will have different music. Sometimes the teacher leading the class will also choose music that he feels is appropriate to use as convening music. Common call-out music includes "Ding Dong", "Shalala", and "Shu Lang". If I were leading a class, I would choose some more trendy and passionate music.

Extended reading: How to buy insurance, which one is better, and step-by-step instructions to avoid these "pitfalls" of insurance