def _get_size(self) -> Size:
        """
        Callable that returns the current `Size`, required by Vt100_Output.
        """
        if self._chan is None:
            return Size(rows=20, columns=79)
        else:
            width, height, pixwidth, pixheight = self._chan.get_terminal_size()
            return Size(rows=height, columns=width)

        Callable that returns the current `Size`, required by Vt100_Output.
        
src/ptpython/contrib/asyncssh_repl.py