Encode and Decode numbers

number_encoder.py

def encode(num: int):
    digits = str(num)
    out = 0
    prev = 0
    
    for tmp in digits:
        tmp = 10 if tmp=='0' else int(tmp)

        cur_prev = prev
        prev = tmp
        if cur_prev <= tmp:
            tmp = tmp - cur_prev
        else:
            tmp = (10 + tmp - cur_prev)%10
            
        out = out*10 + tmp
        print(out)
    
    return out
    
def decode(num: int):
    digits = str(num)
    out = 0
    prev = 0
    
    for tmp in digits:
        tmp = int(tmp)

        tmp = (tmp+prev)%10
        prev = tmp
            
        out = out*10 + tmp
        print(out)
    
    return out

print(encode(3435))

print(decode(3192))