add validation step to ensure bg noise file is not in input folder

        if MISSING_KEYS:

            raise KeyError(f"The following key(s) must be specified : {MISSING_KEYS}")

        # validate preprocessing on concatenated file stage

        if (pre_proc_2 := getattr(cfg, "preprocessing_2", None)) is not None:

            bg_noise_folder = Path(pre_proc_2["background_noise_path"]).parent

            if bg_noise_folder.resolve().absolute() == cfg.input_path.resolve().absolute():

                raise ValueError(f"Background noise file has to be placed outside the input folder!")

        for cond_name, cond_cfg in cfg.get("conditions_to_generate").items():

            type = cond_cfg.get("type")

            if not type: