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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def unmet_expectations(self):
        '''
        Assert that all expectations on the stub have been met.
        '''
        unmet = []
        for exp in self._expectations:
            if not exp.closed(with_counts=True):
                unmet.append(ExpectationNotSatisfied(exp))
        return unmet