<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def session_callback(self, signal):
 """Signalling from stream session. Data - new data available for processing. Playing - Connection is healthy. Retry - if there is no connection to device. """

        if signal == SIGNAL_DATA:
            self.event.new_event(self.data)

        elif signal == SIGNAL_FAILED:
            self.retry()

        if signal in [SIGNAL_PLAYING, SIGNAL_FAILED] and \
                self.connection_status_callback:
            self.connection_status_callback(signal)