public static void SanityCheck()
        {
            // sanity check
            var env = new RepeatObservationEnvironment(agents: 3);

            env.Reset();
            env.Step();
            for (int episode = 0; episode < 100; episode++)
            {
                var observation = (ndarray)env.GetStepResult(null).Item1.obs[0];
                env.SetActions(null, observation);
                env.Step();
                var  step    = env.GetStepResult(null);
                var  success = step.Item1.reward >= 1.99f;
                bool allPass = success.all();
                Trace.Assert(allPass);
            }
        }