<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def set_call_back(self, func):
 """sets callback function for updating the plot. in the callback function implement the logic of reading of serial input also the further processing of the signal if necessary has to be done in this callbak function."""


        self.timer.add_callback(func)
        self.timer.start()