public void AddDialogue(DialogueRow dialogue)
        {
            if (dialogue == null)
            {
                throw new ArgumentNullException(nameof(dialogue));
            }

            if (dialogue.Id == null)
            {
                return;
            }

            this.dialogues[dialogue.Id] = dialogue;

            if (this.dialogues.Count == 1)
            {
                this.startingDialogue = dialogue.Id;
            }
        }
 public static bool IsNullOrNone(this DialogueRow self)
 => self == null || self == DialogueRow.None;
 public static bool IsEnd(this DialogueRow self)
 => self != null &&
 (self is EndDialogueRow || string.Equals(self.Id, EndDialogueRow.Keyword));