Returns all changes from the given changeset.  This includes all of
        the changes from any subsequent changeset, giving precidence to
        later changesets.

def pop_changeset(self, changeset_id: uuid.UUID) -> Dict[bytes, Union[bytes, DeletedEntry]]:
        """
        Returns all changes from the given changeset.  This includes all of
        the changes from any subsequent changeset, giving precidence to
        later changesets.
        """
        if changeset_id not in self.journal_data:
            raise KeyError(changeset_id, "Unknown changeset in JournalDB")

        all_ids = tuple(self.journal_data.keys())
        changeset_idx = all_ids.index(changeset_id)
        changesets_to_pop = all_ids[changeset_idx:]
        popped_clears = tuple(idx for idx in changesets_to_pop if idx in self._clears_at)
        if popped_clears:
            last_clear_idx = changesets_to_pop.index(popped_clears[-1])
            changesets_to_drop = changesets_to_pop[:last_clear_idx]
            changesets_to_merge = changesets_to_pop[last_clear_idx:]
        else:
            changesets_to_drop = ()
            changesets_to_merge = changesets_to_pop

        # we pull all of the changesets *after* the changeset we are
        # reverting to and collapse them to a single set of keys (giving
        # precedence to later changesets)
        changeset_data = merge(*(
            self.journal_data.pop(c_id)
            for c_id
            in changesets_to_merge
        ))

        # drop the changes on the floor if they came before a clear that is being committed
        for changeset_id in changesets_to_drop:
            self.journal_data.pop(changeset_id)

        self._clears_at.difference_update(popped_clears)
        return changeset_data