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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 compatible_firmware_version(self):
 """Returns the DLL's compatible J-Link firmware version. Args: self (JLink):
 the ``JLink`` instance Returns: The firmware version of the J-Link that the DLL is compatible with. Raises: JLinkException: on error. """

        identifier = self.firmware_version.split('compiled')[0]
        buf_size = self.MAX_BUF_SIZE
        buf = (ctypes.c_char * buf_size)()
        res = self._dll.JLINKARM_GetEmbeddedFWString(identifier.encode(), buf, buf_size)
        if res < 0:
            raise errors.JLinkException(res)

        return ctypes.string_at(buf).decode()