static Exception CheckArguments(string type, string subtype, IEnumerable <KeyValuePair <string, string> > parameters) { if (string.IsNullOrEmpty(type)) { throw Failure.NullOrEmptyString(nameof(type)); } if (!VALID_TYPES.Contains(type)) { return(RuntimeFailure.ContentTypeNotStandard("type", type)); } if (string.IsNullOrEmpty(subtype)) { throw Failure.NullOrEmptyString(nameof(subtype)); } return(null); }