using System;

public class Program

{

    public static void Main()

    {

        var cls = new SomeClass<Lion>();

        cls.SomeMethod<Animal>(new Lion());

    }

}

​

public class SomeClass<T1>

{

    public void SomeMethod<T2>(T1 someParameter) where T2 : class

    {

        if(!(someParameter is T2 t2))

        {           

            throw new Exception("Invalid type");

        }

        Console.WriteLine($"Hello from {t2}");

    }

}

​

public class Animal{}

public class Lion : Animal{}