code: def _set_initial_contents(self, contents):
          
          contents = self._encode_contents(contents)
          changed = self._byte_contents != contents
          st_size = len(contents)
  
          if self._byte_contents:
              self.size = 0
          current_size = self.st_size or 0
          self.filesystem.change_disk_usage(
              st_size - current_size, self.name, self.st_dev)
          self._byte_contents = contents
          self.st_size = st_size
          self.epoch += 1
          return changed
docs: Sets the file contents and size.
             Called internally after initial file creation.
  
          Args:
              contents: string, new content of file.
  
          Returns:
              True if the contents have been changed.
  
          Raises:
                IOError: if the st_size is not a non-negative integer,
                     or if st_size exceeds the available file system space