/// <summary>
/// Attempts to add the specified Subject to the collection of People. If a Subject has already
/// been specified, an exception is thrown.
/// </summary>
public void AddSubject(PublicSafetyPerson subject)
{
// There can be only one Subject of a Citation.
if (People.Any(x => CodeValue.ValuesMatch(x.InvolvementType, CitationPersonInvolvementTypes.Subject)))
{
throw new Exception("A Subject already exists on this Citation.");
}
// Make sure the Involvment Type is Correct
subject.InvolvementType = CitationPersonInvolvementTypes.Subject;
// Add the Subject to the Collection of People on the this Citation.
People.Add(subject);
}