public static Professor addProfessors(Professor prof) {
		boolean exist = false;
		int pos = 0;
		if (prof == null)
			return null;
		for (int i = 0; i < FileReadService.profList.size(); i++) {
			if (FileReadService.profList.get(i).equals(prof)) {
				exist = true;
				pos = i;
			}
		}
		if (!exist) {
			FileReadService.profList.add(prof);
			return prof;
		}
		return FileReadService.profList.get(pos);
	}