main.py

from motor_driver import *         # import motor_driver library

# Drive Motor

motor = motor_driver(16,17)        # M2A = 16, M2B = 17

motor.controlSpeed(50)             # move forward at speed 50
utime.sleep(5)                     # sleep 5 second

motor.brake()                      # brake the motor

single_motor_driver.py

import machine
import utime

class motor_driver():
    def __init__(self,MA,MB):
        self.MA = machine.PWM(machine.Pin(MA))
        self.MB = machine.PWM(machine.Pin(MB))
    
    # Will return a integer
    def _convert(self, x, in_min, in_max, out_min, out_max):
        return (x - in_min) * (out_max - out_min) // (in_max - in_min) + out_min

    def controlSpeed(self, speed):
        speed = self._convert(speed,0,100,0,65534)

        if speed > 0:
            self.MA.duty_u16(speed)
            self.MB.duty_u16(0)
        else:
            self.MA.duty_u16(0)
            self.MB.duty_u16(abs(speed))
            
    def brake(self):
        self.controlSpeed(0)