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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def find_dongle_port():
 """Convenience method which attempts to find the port where a BLED112 dongle is connected. This relies on the `pyserial.tools.list_ports.grep method <https://pyserial.readthedocs.io/en/latest/tools.html#serial.tools.list_ports.grep>`_, and simply searches for a port containing the string "Bluegiga" in its description. (This probably only works on Windows at the moment (TODO)). Returns: A string containing the detected port address, or `None` if no matching port was found. """

        logger.debug('Attempting to find Bluegiga dongle...')
        # TODO this will probably only work on Windows at the moment
        ports = list(serial.tools.list_ports.grep('Bluegiga'))
        if len(ports) == 0:
            logger.debug('No Bluegiga-named serial ports discovered')
            return None

        # just return the first port even if multiple dongles
        logger.debug('Found "Bluegiga" serial port at {}'.format(ports[0].device))
        return ports[0].device