def test_iadd(self, evt):
        rval = event.ReturnValue(append_events=[evt])
        rval2 = event.ReturnValue(eat=True, append_events=[evt])
        rset = event.ResultSet()

        rset += rval
        rset += rval2
        rset += None
        assert rset.eat
        assert rset.append_events == [evt, evt]
def _update_dimension(
        self,
        size_diff,
        total_size,
        max_visible_size,
        dimension_request_property):
    if max_visible_size is None:
      is_max_visible_size_unlimited = True
    else:
      is_max_visible_size_unlimited = max_visible_size <= 0