c# - Asserting with OR condition

i am checking a string for three characters ``` Assert.AreEqual(myString.Substring(3,3), "DEF", "Failed as DEF was not observed"); ``` the thing is here it can be `DEF` or `RES`, now to handle this what i can think of is the following ``` bool check = false; if( myString.Substring(3,3) == "DEF" || myString.Substring(3,3) == "RED" ) check = true; Assert.IsTrue(check,"Failed"); Console.WriteLine(""Passed); ``` IS THERE a way i can use some OR thing within Assert p.s i'm writing unit test & yes i will use ternary operator instead....