The point is, a contractual obligation is not the same as "what your job is". Your job contract does not state the details of your day-to-day job, but that is

The point is, a contractual obligation is not the same as "what your job is". Your job contract does not state the details of your day-to-day job, but that is definitely "part of your job", so it is clear that your contract does not define what your job actually is. Conversely, your contract having various obligations in it does not mean that those obligations ARE your job. They are just obligations.