def set_font_face(self, font_face):
        """Replaces the current font face with :obj:`font_face`.

        :param font_face:
            A :class:`FontFace` object,
            or :obj:`None` to restore the default font.

        """
        font_face = font_face._pointer if font_face is not None else ffi.NULL
        cairo.cairo_set_font_face(self._pointer, font_face)
        self._check_status()