<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def on_bandwidth_group_change(self, bandwidth_group):
 """Notification when one of the bandwidth groups change. in bandwidth_group of type :class:`IBandwidthGroup` The bandwidth group which changed. """

        if not isinstance(bandwidth_group, IBandwidthGroup):
            raise TypeError("bandwidth_group can only be an instance of type IBandwidthGroup")
        self._call("onBandwidthGroupChange",
                     in_p=[bandwidth_group])