code: def to_file(self, fp, format_, fps=None, **kwargs):
          
          impl = get_format_class(format_)
          impl.to_file(self, fp, format_, fps=fps, **kwargs)
docs: Write subtitle file to file object.
  
          See :meth:`SSAFile.save()` for full description.
  
          Note:
              This is a low-level method. Usually, one of :meth:`SSAFile.save()`
              or :meth:`SSAFile.to_string()` is preferable.
  
          Arguments:
              fp (file object): A file object, ie. :class:`io.TextIOBase` instance.
                  Note that the file must be opened in text mode (as opposed to binary).