help me

what im do wrong np.meshgrid return only one NDArray, second always null

(scales, ratios) = np.meshgrid(np.array(scales), np.array(ratios));
scales = scales.flatten();
ratios = ratios.flatten();
// Enumerate heights and widths from scales and ratios
var heights = scales / np.sqrt(ratios);
var widths = scales * np.sqrt(ratios);
//Enumerate shifts in feature space
var shifts_y = np.arange(0, shape[0], anchor_stride) * feature_stride;
var shifts_x = np.arange(0, shape[1], anchor_stride) * feature_stride;
(shifts_x, shifts_y) = np.meshgrid(shifts_x, shifts_y);
// Enumerate combinations of shifts, widths, and heights
var (box_widths, box_centers_x) = np.meshgrid(widths, shifts_x);
var (box_heights, box_centers_y) = np.meshgrid(heights, shifts_y);