def METHOD_NAME(capfd, piker_dir):
    orig_watchlist = {
        'dad': ['CIM', 'DOL.TO', 'GM', 'SHOP.TO', 'SPY', 'TSLA'],
        'indexes': ['DAX', 'DIA', 'QQQ', 'SPY'],
        'pharma': ['ATE.VN'],
    }
    list_to_merge = json.dumps({
        'drugs': ['CRACK'],
        'pharma': ['ATE.VN', 'MALI', 'PERCOCET']
    })
    expected_out = {
        'dad': ['CIM', 'DOL.TO', 'GM', 'SHOP.TO', 'SPY', 'TSLA'],
        'indexes': ['DAX', 'DIA', 'QQQ', 'SPY'],
        'pharma': ['ATE.VN', 'MALI', 'PERCOCET'],
        'drugs': ['CRACK']
    }
    wl.write_to_file(orig_watchlist, piker_dir)
    run(f"piker watchlists -d {piker_dir} merge", list_to_merge)
    out = wl.ensure_watchlists(piker_dir)
    assert out == expected_out