code: def set_large_file_size(self, st_size):
          
          self._check_positive_int(st_size)
          if self.st_size:
              self.size = 0
          if self.filesystem:
              self.filesystem.change_disk_usage(st_size, self.name, self.st_dev)
          self.st_size = st_size
          self._byte_contents = None
docs: Sets the self.st_size attribute and replaces self.content with None.
  
          Provided specifically to simulate very large files without regards
          to their content (which wouldn't fit in memory).
          Note that read/write operations with such a file raise
              :py:class:`FakeLargeFileIoException`.
  
          Args:
            st_size: (int) The desired file size
  
          Raises:
            IOError: if the st_size is not a non-negative integer,
                     or if st_size exceeds the available file system space