def METHOD_NAME(xmin, xmax, ymin, ymax):
    proj = ccrs.PlateCarree()
    nx = 4
    ny = 2
    target_x, target_y, extent = img_trans.mesh_projection(
        proj, nx, ny,
        x_extents=(xmin, xmax),
        y_extents=(ymin, ymax))
    if xmin is None:
        xmin = proj.x_limits[0]
    if xmax is None:
        xmax = proj.x_limits[1]
    if ymin is None:
        ymin = proj.y_limits[0]
    if ymax is None:
        ymax = proj.y_limits[1]
    assert_array_equal(extent, [xmin, xmax, ymin, ymax])
    assert_array_equal(np.diff(target_x, axis=1), (xmax - xmin) / nx)
    assert_array_equal(np.diff(target_y, axis=0), (ymax - ymin) / ny)