code: def generate_anchors(
      stride=16, sizes=(32, 64, 128, 256, 512), aspect_ratios=(0.5, 1, 2)
  ):
      
      return _generate_anchors(
          stride,
          np.array(sizes, dtype=np.float) / stride,
          np.array(aspect_ratios, dtype=np.float),
      )
docs: Generates a matrix of anchor boxes in (x1, y1, x2, y2) format. Anchors
      are centered on stride / 2, have (approximate) sqrt areas of the specified
      sizes, and aspect ratios as given.