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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 resolve_blobs(self, iter_blobs):
 """Resolve the blobs given in blob iterator. This will effectively remove the index entries of the respective path at all non-null stages and add the given blob as new stage null blob. For each path there may only be one blob, otherwise a ValueError will be raised claiming the path is already at stage 0. :raise ValueError: if one of the blobs already existed at stage 0 :return: self :note: You will have to write the index manually once you are done, i.e. index.resolve_blobs(blobs).write() """

        for blob in iter_blobs:
            stage_null_key = (blob.path, 0)
            if stage_null_key in self.entries:
                raise ValueError("Path %r already exists at stage 0" % blob.path)
            # END assert blob is not stage 0 already

            # delete all possible stages
            for stage in (1, 2, 3):
                try:
                    del(self.entries[(blob.path, stage)])
                except KeyError:
                    pass
                # END ignore key errors
            # END for each possible stage

            self.entries[stage_null_key] = IndexEntry.from_blob(blob)
        # END for each blob

        return self