JObject IReferences.GetReferred(JObject obj)
        {
            var refProperty = obj.Property("$ref");

            if (refProperty != null && !(refProperty.Value is null))
            {
                var refId = refProperty.Value.Value <string>();
                if (_refs.TryGetReferred(refId, out var refObj))
                {
                    return(refObj);
                }
                else
                {
                    throw new InvalidOperationException($"The reference to '{refId}' does not exist.");
                }
            }
            return(obj);
        }