code: def _getDevMajorMinor(self, devpath):
          
          fstat = os.stat(devpath)
          if stat.S_ISBLK(fstat.st_mode):
              return(os.major(fstat.st_rdev), os.minor(fstat.st_rdev))
          else:
              raise ValueError("The file %s is not a valid block device." % devpath)
docs: Return major and minor device number for block device path devpath.
          @param devpath: Full path for block device.
          @return:        Tuple (major, minor).