def getDevice(self):
        """
        Retrieves the device containing the file.  The inode number and device
        number together uniquely identify the file, but the device number is
        not necessarily consistent across reboots or system crashes.

        @raise NotImplementedError: if the platform is Windows, since the
            device number would be 0 for all partitions on a Windows platform

        @return: a number representing the device
        @rtype: L{int}

        @since: 11.0
        """
        if platform.isWindows():
            raise NotImplementedError

        st = self._statinfo
        if not st:
            self.restat()
            st = self._statinfo
        return st.st_dev

        Retrieves the device containing the file.  The inode number and device
        number together uniquely identify the file, but the device number is
        not necessarily consistent across reboots or system crashes.

        @raise NotImplementedError: if the platform is Windows, since the
            device number would be 0 for all partitions on a Windows platform

        @return: a number representing the device
        @rtype: L{int}

        @since: 11.0
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/filepath.py