public IList <Expression> GetMemberMappingExpressions()
        {
            if (_memberMappingExpressions?.Count == MappingExpressions.Count)
            {
                return(_memberMappingExpressions ?? Enumerable <Expression> .EmptyArray);
            }

            return(_memberMappingExpressions = MappingExpressions.Filter(IsMemberMapping).ToList());
        }
        public List <Expression> GetMemberMappingExpressions()
        {
            if (_memberMappingExpressions?.Count == MappingExpressions.Count)
            {
                return(_memberMappingExpressions ?? new List <Expression>(0));
            }

            return(_memberMappingExpressions = MappingExpressions.Filter(IsMemberMapping).ToList());
        }