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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 add_license(self, contents):
 """Adds the given ``contents`` as a new custom license to the J-Link. Args: self (JLink):
 the ``JLink`` instance contents: the string contents of the new custom license Returns: ``True`` if license was added, ``False`` if license already existed. Raises: JLinkException: if the write fails. Note: J-Link V9 and J-Link ULTRA/PRO V4 have 336 Bytes of memory for licenses, while older versions of 80 bytes. """

        buf_size = len(contents)
        buf = (ctypes.c_char * (buf_size + 1))(*contents.encode())

        res = self._dll.JLINK_EMU_AddLicense(buf)

        if res == -1:
            raise errors.JLinkException('Unspecified error.')
        elif res == -2:
            raise errors.JLinkException('Failed to read/write license area.')
        elif res == -3:
            raise errors.JLinkException('J-Link out of space.')

        return (res == 0)