Why don't fortune tellers know fortune tellers?

Why don't fortune tellers do their own calculations? It's not what you said, but there are rules, and fortune tellers can't calculate for themselves. Because you will get involved in your personal feelings. There is also fortune telling, that is, spying on secrets, which is considered a curse on yourself. Another rule is that it is not a big event. For example, if someone says you are accurate, then you can calculate what will happen in a few days. This doesn't count. There is also the fact that national luck does not count. China has only had two heats in five thousand years. You counted the luck of the country. When you finish, you will be cursed. One is Yuan Tiangang, and the other is who forgot. They wrote a push-back map and calculated the fate of the world and the country in each dynasty. It's too early, damn it