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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 outputs(ctx, client, revision, paths):
 r"""Show output files in the repository. <PATHS> Files to show. If no files are given all output files are shown. """

    graph = Graph(client)
    filter = graph.build(paths=paths, revision=revision)
    output_paths = graph.output_paths

    click.echo('\n'.join(graph._format_path(path) for path in output_paths))

    if paths:
        if not output_paths:
            ctx.exit(1)

        from renku.models._datastructures import DirectoryTree
        tree = DirectoryTree.from_list(item.path for item in filter)

        for output in output_paths:
            if tree.get(output) is None:
                ctx.exit(1)
                return