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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 __get_delta_files(self):
 """Search for delta files and return a dict of Delta objects, keyed by directory names."""

        files = [(d, f) for d in self.dirs for f in listdir(d) if isfile(join(d, f))]

        deltas = OrderedDict()
        for d, f in files:
            file_ = join(d, f)

            if not Delta.is_valid_delta_name(file_):
                continue

            delta = Delta(file_)

            if d not in deltas:
                deltas[d] = []
            deltas[d].append(delta)

        # sort delta objects in each bucket
        for d in deltas:
            deltas[d].sort(key=lambda x: (x.get_version(), x.get_priority(), x.get_name()))

        return deltas