public override string ToString()
{
StringBuilder simCardsDescription = new StringBuilder();
_simCards.ForEach(simCard => simCardsDescription.Append(simCard.GetDescription() + "\n"));
return($"Mobile phone model: {MobileModel}.\n"
+ Screen.GetDescription() + "\n"
+ Microphone.GetDescription() + "\n"
+ Battery.GetDescription() + "\n"
+ Speaker.GetDescription() + "\n"
+ simCardsDescription + "\n"
+ "\n");
}
