code: def AddFileReadData(self, path, file_data_path):
      
      if self.file_system.FileEntryExistsByPath(path):
        raise ValueError('Path: {0:s} already set.'.format(path))
  
      with open(file_data_path, 'rb') as file_object:
        file_data = file_object.read()
  
      self._AddParentDirectories(path)
      self.file_system.AddFileEntry(path, file_data=file_data)
docs: Adds a "regular" file to the fake file system.
  
      Args:
        path (str): path of the file within the fake file system.
        file_data_path (str): path of the file to read the file data from.
  
      Raises:
        ValueError: if the path is already set.