No restraining order or injunctive relief may be granted to any complainant who has failed to comply with any legal obligation which is involved in the labor dispute in question, or who has failed to make every reasonable effort to settle the dispute either by negotiation or with the aid of any available machinery of governmental mediation or voluntary arbitration, but nothing in this section requires a court to await the action of any such tribunal if irreparable injury is threatened.
Wis. Stat. § 103.57