{cpu1} displays always 0% when set to display two cpu cores like this: {cpu0}{cpu1}

def _fetch_cpu(self, percpu=False):
    if percpu:
    return ps.cpu_percent(interval=0, percpu=True)

Here psutil.cpu_percent is called twice almost simultaneously which means time between the first call and the second call is too short to measure the {cpu1} utilization.

I suggest that provide an option like {cpuall} to display all the cpu cores and call the psutil.cpu_percent only once per update.