def METHOD_NAME(channel_PLN):
    # given
    channel_id = graphene.Node.to_global_id("Channel", channel_PLN.id)
    error_code = ShippingErrorCode.DUPLICATED_INPUT_ITEM.value
    errors = defaultdict(list)
    # when
    result = BaseChannelListingMutation.clean_channels(
        None, {"remove_channels": [channel_id, channel_id]}, errors, error_code
    )
    # then
    assert result == {}
    assert errors["remove_channels"][0].code == error_code