def image_center_crop(img):
    """
    Makes a square center crop of an img, which is a [h, w, 3] numpy array.
    Returns [min(h, w), min(h, w), 3] output with same width and height.
    For cropping use numpy slicing.
    """

    h,w,_ = img.shape
    length = min(h, w)
    l = min(h, w)

    cropped_img = img[:, (w - h)//2 : (w - h)//2 + l, :] if w >= h else img[(h - w)//2 : (h - w)//2 + l, :, :]

    # checks for errors
    h, w, c = img.shape
    assert cropped_img.shape == (min(h, w), min(h, w), c), "error in image_center_crop!"

    return cropped_img