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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 cli(ctx):
 """ CLI for maildirs content analysis and deletion. """

    level = logger.level
    try:
        level_to_name = logging._levelToName
    # Fallback to pre-Python 3.4 internals.
    except AttributeError:
        level_to_name = logging._levelNames
    level_name = level_to_name.get(level, level)
    logger.debug('Verbosity set to {}.'.format(level_name))

    # Print help screen and exit if no sub-commands provided.
    if ctx.invoked_subcommand is None:
        click.echo(ctx.get_help())
        ctx.exit()

    # Load up global options to the context.
    ctx.obj = {}