What is the legal implication of an affirmation followed by an exception?

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If a person affirms a debt, such as saying, 'I owe you one hundred except ten,' they are affirming the remaining ninety. The exception prevents what would otherwise be included from entering the statement. Conversely, if they were to admit the excepted ten, they would not be permitted to later deny it. Similarly, affirming ownership of a house except for one specific room implies affirmation of everything else in the house.