docs: def CheckMounts(filename):
    """Parses the currently mounted devices."""
    with io.open(filename, "r") as fd:
      for line in fd:
        try:
          device, mnt_point, fs_type, _ = line.split(" ", 3)
        except ValueError:
          continue
        if fs_type in ACCEPTABLE_FILESYSTEMS:
          if os.path.exists(device):
            yield device, fs_type, mnt_point