/// <summary>
/// Adds an IPossessable construct, such as a person place or thing, to the collection of Entity instances the PossessivePronoun "Owns",
/// and sets its owner to be the PossessivePronoun.
/// If the item is already possessed by the current instance, this method has no effect.
/// </summary>
/// <param name="possession">The possession to add.</param>
public void AddPossession(IPossessable possession)
{
PossessesFor?.AddPossession(possession);
possessions = possessions.Add(possession);
}
/// <summary>
/// Adds a possession to the collection of items this instance possesses.
/// </summary>
/// <param name="possession">The possession to add.</param>
public void AddPossession(IPossessable possession)
{
PossessesFor = PossessesFor ?? PreviousWord as IEntity;
PossessesFor?.AddPossession(possession);
possessions = possessions.Add(possession);
}