uln2003 for MicroPython has been in github, here's the link. But it's work for microbit, so I change a little to transplant for my NodeMCU's ESP-32s. Here's the example:

import Stepper
from machine import Pin
s1 = Stepper.create(Pin(16,Pin.OUT),Pin(17,Pin.OUT),Pin(5,Pin.OUT),Pin(18,Pin.OUT), delay=2)
s1.step(100)
s1.step(100,-1)
s1.angle(180)
s1.angle(360,-1)

function angle is angle, and the PIN map: IN1 link PIN_16 IN2 link PIN_17 IN3 link PIN_5 IN4 link PIN_18 My uln2003 board like this, and stepper runing: