Break block faster

[privatemethod]

Hello

I tried to make a script which allows me to break a block faster when my variable is set to a specific role.

I made command which changes my {rol.%player%} from <none> to "houthakker" (its something in Dutch).

Now my question is why my code is not working or do you guys know another way to fix this

My Code:

on block break:
    if event-block is stone:
        if {rol.%player%} is "houthakker":
            set {_block} to targeted block
            show block break stage 4 at {_block}