code: def uuid(dev=None):
      '''
      Return the bcache UUID of a block device.
      If no device is given, the Cache UUID is returned.
  
      CLI example:
  
      .. code-block:: bash
  
          salt '*' bcache.uuid
          salt '*' bcache.uuid /dev/sda
          salt '*' bcache.uuid bcache0
  
      '''
      try:
          if dev is None:
              # take the only directory in /sys/fs/bcache and return it's basename
              return list(salt.utils.path.os_walk('/sys/fs/bcache/'))[0][1][0]
          else:
              # basename of the /sys/block/{dev}/bcache/cache symlink target
              return os.path.basename(_bcsys(dev, 'cache'))
      except Exception:
          return Falsf uuid(dev=None):
      '''
      Return the bcache UUID of a block device.
      If no device is given, the Cache UUID is returned.
  
      CLI example:
  
      .. code-block:: bash
  
          salt '*' bcache.uuid
          salt '*' bcache.uuid /dev/sda
          salt '*' bcache.uuid bcache0
  
      '''
      try:
          if dev is None:
              # take the only directory in /sys/fs/bcache and return it's basename
              return list(salt.utils.path.os_walk('/sys/fs/bcache/'))[0][1][0]
          else:
              # basename of the /sys/block/{dev}/bcache/cache symlink target
              return os.path.basename(_bcsys(dev, 'cache'))
      except Exception:
          return False
docs: Return the bcache UUID of a block device.
      If no device is given, the Cache UUID is returned.
  
      CLI example:
  
      .. code-block:: bash
  
          salt '*' bcache.uuid
          salt '*' bcache.uuid /dev/sda
          salt '*' bcache.uuid bcache0