How do I remove a unused generic type in a method? Follow

"T2 arg2" is a unused parameter, and i remove it.

public void Method1<T1,T2,TOut>(T1 arg1, T2 arg2, TOut arg3) {}

but "T2" still in signature.

public void Method1<T1,T2,TOut>(T1 arg1, TOut arg3) {}

Is this possible, or am I missing something obvious?

Thank you!