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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 join(cls, diffs: Iterable['DBDiff']) -> 'DBDiff': """ Join several DBDiff objects into a single DBDiff object. In case of a conflict, changes in diffs that come later in ``diffs`` will overwrite changes from earlier changes. """

        tracker = DBDiffTracker()
        for diff in diffs:
            diff.apply_to(tracker)
        return tracker.diff()