code: def upscale(image, ratio):
      
      if not isinstance(image, np.ndarray):
          raise ValueError('Expected ndarray')
      if ratio < 1:
          raise ValueError('Ratio must be greater than 1 (ratio=%f)' % ratio)
      width = int(math.floor(image.shape[1] * ratio))
      height = int(math.floor(image.shape[0] * ratio))
      channels = image.shape[2]
      out = np.ndarray((height, width, channels), dtype=np.uint8)
      for x, y in np.ndindex((width, height)):
          out[y, x] = image[int(math.floor(y / ratio)), int(math.floor(x / ratio))]
      return out
docs: return upscaled image array
      Arguments:
      image -- a (H,W,C) numpy.ndarray
      ratio -- scaling factor (>1)