Oral Proof against a Written Document

Many times, a claim is raised by one party that the parties to the lease agreement have agreed on something which is different from the provisions of the lease agreement.
Thus, suppose that in the lease it is written which electrical products the landlord will leave in the apartment.
But the parties orally agreed that the landlord would leave additional products in the apartment for the tenant to use.

In this matter, the rule is that whoever seeks to bring oral evidence against a document is in an inferior position, and in order for his claim to be accepted it is incumbent upon him to prove and convince the court of his justification.
Otherwise, his claim will be rejected