Conditions of an insurance policy requiring that notice of an "occurrence" be given to an insurance carrier as soon as practicable and that suit papers be forwarded immediately are valid and enforceable. Greer v. Zurich Ins. Co., 441 S.W.2d 15, 30 (Mo. 1969). The burden of proof upon the question of compliance with the provisions of a policy ordinarily rests upon the insured, if he seeks to recover indemnity under the policy, or upon the injured party who stands in the shoes of the insured. Nevertheless, while it may be stated generally that the insured has the burden of proving the facts essential to the garnishee's liability, if the garnishee seeks to escape coverage solely because of an alleged breach of a policy provision requiring the insured to cooperate with the insurer, the burden is upon the insurer to prove facts that would make that provision relieve the insurer from liability. Meyers v. Smith, 375 S.W.2d 9, 15 (Mo. 1964).