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 getAp2(self):
        ret =math.acos(((self.getLenp1() * self.getLenp1() + self.getLenp3() * self.getLenp3()) - self.getLenp2() * self.getLenp2()) / (2* self.getLenp1() * self.getLenp3()))
        return ret