How to stack videos vertically in moviepy?

While using moviepy, I use clips_array which stacks clips side by side. How can I make this vertically ?

this is my code

from conf import SAMPLE_INPUTS, SAMPLE_OUTPUTS
from moviepy.editor import *

length = 10

clip1 = VideoFileClip('vid1.mp4').subclip(0, 0 + length)
clip2 = VideoFileClip('vid2.mp4').subclip(0, 0 + length)

combined = clips_array([[clip1, clip2]])
combined = combined.resize(height=1920)
combined = combined.crop(x1=1166.6, y1=0, x2=2246.6, y2=1920)
combined.write_videofile('test.mp4')