<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def scatter(self, *args, **kwargs):
 """Add a scatter plot."""

        cls = _make_class(ScatterVisual,
                          _default_marker=kwargs.pop('marker', None),
                          )
        return self._add_item(cls, *args, **kwargs)