Am I trying to use a variable or pass a value by reference or by value?

I commented out the "private:" line in the code to see what would happen and latest error is

Arduino: 1.8.2 (Windows 10), Board: "Arduino/Genuino Uno"

C:\Users\Master\Documents\Arduino\led_example\led_example.ino: In function 'void setNextCloud()':

led_example:78: error: no matching function for call to 'DailyTimer::isActive()'

   if(sunRiseSunSet.isActive())

                             ^

C:\Users\Master\Documents\Arduino\led_example\led_example.ino:78:29: note: candidate is:

In file included from C:\Users\Master\Documents\Arduino\led_example\led_example.ino:1:0:

sketch\DailyTimer.h:79:17: note: static bool DailyTimer::isActive(DailyTimer*)

     static bool isActive(DailyTimer* instance);

                 ^

sketch\DailyTimer.h:79:17: note:   candidate expects 1 argument, 0 provided

exit status 1
no matching function for call to 'DailyTimer::isActive()'

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

I'm assuming the code compiles fine for you, what am I doing wrong here?