程序运行错误，请根据上方提示,找到对应lua文件修改程序!
[2020-08-13 18:54:59.412] lua /lua/testCamera.lua:74: attempt to call field 'cameraopen' (a nil value)
[2020-08-13 18:54:59.412] stack traceback:
[2020-08-13 18:54:59.412] /lua/testCamera.lua:74: in function 'cb'
[2020-08-13 18:54:59.412] /lua/sys.lua:371: in function 'run'
[2020-08-13 18:54:59.412] /lua/main.lua:67: in main chunk