1. School of Mathematics, Southwestern University of Finance and Economics, Chengdu, Sichuan, People's Republic of China
2. College of Big Data and Statistics, Sichuan Tourism University, Chengdu, Sichuan, People's Republic of China
3. School of Mathematical Sciences, Sichuan Normal University, Chengdu, Sichuan, People's Republic of China
4. School of Mathematics, Chengdu Normal University, Chengdu, Sichuan, People's Republic of China