'This method saves item delta time and shows updated progress bar with calculated eta'

def progress(self, deltaTime, newAmount):

    if ((len(self._times) <= ((self._max * 3) / 100)) or (newAmount > self._max)):
        eta = None
    else:
        midTime = (sum(self._times) / len(self._times))
        midTimeWithLatest = ((midTime + deltaTime) / 2)
        eta = (midTimeWithLatest * (self._max - newAmount))
    self._times.append(deltaTime)
    self.update(newAmount)
    self.draw(eta)
