>>> test(intv((3,4)),intv((1,2))+2)
'leeg'
>>> test(intv((1,2))+2,intv((3,4)))
'legg'

intv((3,4))=   Interval [2.9999997615814208984375, 4.000000476837158203125]
intv((1,2))+2= Interval [2.9999997615814208984375, 4.00000095367431640625]