docs: def _initialize(self, path):
          """ Find metadata tree root, detect format version """
          # Find the tree root
          root = os.path.abspath(path)
          try:
              while ".fmf" not in next(os.walk(root))[1]:
                  if root == "/":
                      raise utils.RootError(
                          "Unable to find tree root for '{0}'.".format(
                              os.path.abspath(path)))
                  root = os.path.abspath(os.path.join(root, os.pardir))
          except StopIteration:
              raise utils.FileError("Invalid directory path: {0}".format(root))
          log.info("Root directory found: {0}".format(root))
          self.root = root
          # Detect format version
          try:
              with open(os.path.join(self.root, ".fmf", "version")) as version:
                  self.version = int(version.read())
                  log.info("Format version detected: {0}".format(self.version))
          except IOError as error:
              raise utils.FormatError(
                  "Unable to detect format version: {0}".format(error))
          except ValueError:
              raise utils.FormatError("Invalid version format")