private boolean checkConstraints() {
		if (this.licenseNumber == null)
			return false;
		if (this.insuranceNumber == null)
			return false;
		if (this.branch == null)
			return false;
		if (this.vehicleGroup == null)
			return false;
		if (this.actualKm < 0)
			return false;
		return true;
	}