图像检索：从给定的一组图片中检索出带有足球的图片，返回10个检索结果-Find the images containing footballs (i.e., images 990.jpg, 991.jpg, …, 999.jpg)　dataset1. Each time, you pick one of these football images (i.e., images 990.jpg, 991.jpg, …, 999.jpg) as the input image to the program and it returns n images. (n is set to 10 by default, but you may change it.) As there are 10 football images in dataset1, the final retri　performance is the average of the 10 retri　results.