SysTick_Handler() in mbed-os 5

How do I set SysTick_Handler() in mbed-os 5?
I have mbed-os 2 example where SysTick_Handler() function is defined in stm32f7xx_it.c file including stm32f7xx_it.h header template where it is declared but I find no similar templates concept in mbed-os 5. Is it because by default it uses threads instead of handlers? But how to achieve the same result with RTOS?
I guess this handler is set in startup_stm32f769xx.s boot loader but I am not sure.
Please advice.