docs: def private_path(self):
          """Get the path to a directory which can be used to store arbitrary data
  
          This directory should not conflict with any of the repository internals.
          The directory should be created if it does not already exist.
  
          """
          path = os.path.join(self.path, '.hg', '.private')
          try:
              os.mkdir(path)
          except OSError as e:
              if e.errno != errno.EEXIST:
                  raise
          return path