from machine import Pin
import time
key1=Pin(14,Pin.IN,Pin,PULL_UP)
key2=Pin(27,Pin.IN,Pin,PULL_UP)
key3=Pin(26,Pin.IN,Pin,PULL_UP)
key4=Pin(25,Pin.IN,Pin,PULL_UP)
led1=Pin(15,Pin.OUT)
led2=Pin(2,Pin.OUT)
led3=Pin(0,Pin.OUT)
led4=Pin(4,Pin.OUT)
KEY1_PRESS,KEY2_PRESS,KEY3_PRESS,KEY4_PRESS=1,2,3,4
key_en=1
def key_scan():
    global key_en
    if key_en==1 and(key1.value()==0 or key2.value()==0 
    or key3.value()==0 or key4.value()==0):
    time.sleep_ms(10)
    key_en=0
     if key1.value()==0:
        return KEY1_PRESS
     elif key2.value()==0:
        return KEY2_PRESS
     elif key3.value()==0:
        return KEY3_PRESS
     elif key4.value()==0:
        return KEY4_PRESS
    elif key1.value()==1 and key2.value()==1 and key3.value()==1 and key4.value()==1:
        key_en=1
    return 0
if __name__=="__main__":
    key=0
    i_led1,i_led2,i_led3,i_led4=0,0,0,0
    led1.value(i_led1)
    led2.value(i_led2)
    led3.value(i_led3)
    led4.value(i_led4)   
    while True:
        key=key_scan()
        if key==KEY1_PRESS:
            i_led1=not i_led1
            led1.value(i_led1)
        elif key==KEY2_PRESS:
            i_led2=not i_led2 
            led2.value(i_led2) 
        elif key==KEY3_PRESS:
            i_led3=not i_led3
            led3.value(i_led3)
        elif key==KEY4_PRESS:
            I_LED4=not i_led4
            led4.value(i_led4)