Asking for do_reset

[Vreyka]

Hi everyone,
I'm stucking in understand how do_reset work in leaky.py
As what i understand in the code of leaky.py, the do_reset will return 1 when the reset = 0 and spk =1 but and 0 if all reset and spk equal 1 or 0. But what if reset = 1 and spk =0?
I also wonder about these assumptions. If the mem received in the loop for somthings > threshold, then the reset = 1. After that, it update with an input. If the input's large enough to make spk = 1 and the do_reset after that will be 0 and mem doesn't reset follow the next code in function. And if it can't make spk = 1, the do_rest will be -1 then it will increase the mem with the voltage threshold?
Can someone explain it to me. Does it make a bug here or I'm misunderstand somthings?
Thanks.