code: def GetRootFileEntry(self):
      
      if platform.system() == 'Windows':
        # Return the root with the drive letter of the volume the current
        # working directory is on.
        location = os.getcwd()
        location, _, _ = location.partition('\\')
        location = '{0:s}\\'.format(location)
      else:
        location = '/'
  
      if not os.path.exists(location):
        return None
  
      path_spec = os_path_spec.OSPathSpec(location=location)
      return self.GetFileEntryByPathSpec(path_spec)
docs: Retrieves the root file entry.
  
      Returns:
        OSFileEntry: a file entry or None if not available.