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 setTail(self, pt):
        self.pt = pt
        self.Tail.Eq(pt)
        self.Head.setPoint(self.pt.x + self.x, self.pt.y + self.y)