Cannot use wgstateflag to deny mob randomspawn in specific regions :(

[digital-r]

May be i just not understand some of mechanics, but i cannot deny mob spawning in specific regions:
Let we have test region TEST with flag firework-damage set to DENY.
How i must set condition wgstateflag for random spawners to deny spawn in this TEST region?

• wgstateflag{flag=firework-damage;action=false} dont works.
• wgstateflag{flag=firework-damage;action=false} false dont works too

Please, help!