mistake

If a BARBER makes a mistake,
it's
a new hair style.
If a POLITICIAN makes a
mistake, it's a new law.
If a SCIENTIST makes a mistake, it's a new invention.
If a TAILOR makes a mistake,
it's a
new fashion.
If a TEACHER makes a
mistake, it's a new theory but.... If a STUDENT
makes a
mistake, it's a????.