def add_cli_clear_bel_namespace(main: click.Group) -> click.Group:  
@main.command()<EOL>@click.pass_obj<EOL>def drop(manager: BELNamespaceManagerMixin):<EOL><INDENT>"""<STR_LIT>"""<EOL>namespace = manager.drop_bel_namespace()<EOL>if namespace:<EOL><INDENT>click.echo(f'<STR_LIT>')<EOL><DEDENT><DEDENT>return main<EOL>
Add a ``clear_bel_namespace`` command to main :mod:`click` function.