timer strange ?

[trix]

hello,
i,am busy to adjust the code from a libary (micropython-stepper 1.0.3),
to do the things witch i want it to do (acc & decc).
no i see that the configure the timer on a different way then what i learn.
i learn something like:

timer_0.init(mode=, period=, callback=)

where you have by mode the options:
periodic
one_shot

now i see in the libary that te used a timer configuration:

timer.init(freq = self.steps_per_sec,callback = self._timer_callback)

do someone now why the 2e way is also working ?
tnx.