I think he just misused terminology, Philip.
I think he has an object, referenced by the variable monomiial (or maybe Monomio--he uses different names in different posts) and that object has a property named exponent (or maybe grado--again, different names in different posts).
SO I think the answer is "yes".
I think if he simply uses
monomial.exponent.sup() (or maybe it is
Monomio.grado.sup()??) it will work.
It will not work as he showed it: (monomial.exponent).sup because he omitted the () after sup.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.