fix flip comments, test=develop closes:#21799
@ -34,7 +34,7 @@ def flip(im):
"""
Return the flipped image.
Flip an image along the horizontal direction.
im: input image, (H x W x K) ndarrays
im: input image, (K x H x W) ndarrays
if len(im.shape) == 3:
return im[:, :, ::-1]