def METHOD_NAME(preds, target, metric_func):
    # shape: preds [BATCH_SIZE, 1, Time] , target [BATCH_SIZE, 1, Time]
    # or shape: preds [NUM_BATCHES*BATCH_SIZE, 1, Time] , target [NUM_BATCHES*BATCH_SIZE, 1, Time]
    return metric_func(preds, target).mean()