True if the task is a GS Task and uses paral_kgb with the given value.

def uses_paral_kgb(self, value=1):
        """True if the task is a GS Task and uses paral_kgb with the given value."""
        paral_kgb = self.get_inpvar("paral_kgb", 0)
        # paral_kgb is used only in the GS part.
        return paral_kgb == value and isinstance(self, GsTask)