def sample_batch_trajectories(self, rollout_length):
results = []<EOL>for i in range(self.num_envs):<EOL><INDENT>results.append(self.sample_rollout_single_env(rollout_length))<EOL><DEDENT>return np.stack(results, axis=-<NUM_LIT:1>)<EOL>
Return indexes of next random rollout