public static void UpdateVerbConjugationHistory(UserProfile profile, VerbConjugation conj, AnswerScore score)
        {
            var vchi = profile.History.VerbConjugationHistory.Find(v => v.VerbConjugation.Equals(conj));

            if (vchi == null)
            {
                vchi = new VerbConjugationHistoryItem() { VerbConjugation = conj };
                profile.History.VerbConjugationHistory.Insert(0, vchi);
            }

            HistoryItemOperations.UpdateHistoryItemWithSuccessFailureAndTimestamp(vchi, score);
        }
        public static bool DoesTheUserKnowVerbConjugation(UserProfile profile, VerbConjugation conj)
        {
            foreach (var vchi in profile.History.VerbConjugationHistory)
            {
                if (!vchi.VerbConjugation.Equals(conj))
                {
                    continue;
                }

                if (IsVerbConjugationSuccessful(vchi))
                {
                    return true;
                }
            }

            return false;
        }