<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add_port_callback(self, port, cb):
 """Add a callback for data that comes on a specific port"""

        logger.debug('Adding callback on port [%d] to [%s]', port, cb)
        self.add_header_callback(cb, port, 0, 0xff, 0x0)