'Load the IRQ file and update the internal dict'

def __update(self):

    self.reset()
    if (not os.path.exists(self.IRQ_FILE)):
        return self.stats
    try:
        with open(self.IRQ_FILE) as irq_proc:
            time_since_update = getTimeSinceLastUpdate('irq')
            self.__header(irq_proc.readline())
            for line in irq_proc.readlines():
                irq_line = self.__humanname(line)
                current_irqs = self.__sum(line)
                irq_rate = int(((current_irqs - self.lasts.get(irq_line)) if self.lasts.get(irq_line) else (0 // time_since_update)))
                irq_current = {'irq_line': irq_line, 'irq_rate': irq_rate, 'key': self.get_key(), 'time_since_update': time_since_update}
                self.stats.append(irq_current)
                self.lasts[irq_line] = current_irqs
    except (OSError, IOError):
        pass
    return self.stats
