def OnDataChanged(self, sensor_data):
    self.previousSystemData = self.currentSystemData
    self.currentSystemData = sensor_data
    if self.previousSystemData:
        self.done = True
def OnDataChanged(self, sensor_data):
    self.previousSystemData = self.currentSystemData
    self.currentSystemData = sensor_data
    if self.previousSystemData:
        self.done = True