Buggy python submission (verdict: Runtime Error):
import numpy as np
def binary(_x):
    x = _x
    l = int(np.log2(x) + 1)
    res = [0] * l
    
    for i in range(l):
        res[i] += x%2
        x = int(x/2)
    return res


def a_xor(lis, i, sub, sub_max):
    return lis[i] * ( ( sub_max - sub + 1 ) % 2 )


def b_xor(lis, i, sub, sub_max):
    return lis[i] * ( ( sub_max - sub ) % 2 )


def main():
    A, B = map(int, input().split())
    bin_a = binary(A)
    bin_b = binary(B)
    odd_even_vec = [0] * len(bin_b)

    #print("a")
    sub = 0
    sub_max = 0
    for i, bit in enumerate(bin_a):
        if i == 0:
            odd_even_vec[i] += bit%2
        else:
            k = i-1
            sub += bit * 2**k
            sub_max += 2**k
            odd_even_vec[i] += a_xor(bin_a, i, sub, sub_max)
        #print(odd_even_vec, sub, sub_max)

    #print("b")
    sub = 0
    sub_max = 0
    for i, bit in enumerate(bin_b):
        if i == 0:
            odd_even_vec[i] += bit%2
        else:
            k = i-1
            sub += bit * 2**k
            sub_max += 2**k
            odd_even_vec[i] += b_xor(bin_b, i, sub, sub_max)
            
        #print(odd_even_vec, sub, sub_max)
        
    res = 0
    for i, bit in enumerate(odd_even_vec):
        res += bit%2 * 2**i

    print (res)

    
main()


Fixed submission:
def F(n):
    res = 0
    if n % 4 == 0:
        res = n
    elif n % 4 == 1:
        res = 1
    elif n % 4 == 2:
        res = 1^n
    else:
        res = 0
        
    return res

def main():
    A, B = map(int, input().split())
    ans = F(A-1) ^ F(B)

    #print(A, B, F(A-1), F(B))

    print(ans)

main()

Buggy python submission (verdict: Runtime Error):
import numpy as np
def binary(_x):
    x = _x
    l = int(np.log2(x) + 1)
    res = [0] * l
    
    for i in range(l):
        res[i] += x%2
        x = int(x/2)
    return res


def a_xor(lis, i, sub, sub_max):
    return lis[i] * ( ( sub_max - sub + 1 ) % 2 )


def b_xor(lis, i, sub, sub_max):
    return lis[i] * ( ( sub_max - sub ) % 2 )


def main():
    A, B = map(int, input().split())
    bin_a = binary(A)
    bin_b = binary(B)
    odd_even_vec = [0] * len(bin_b)

    print("a")
    sub = 0
    sub_max = 0
    for i, bit in enumerate(bin_a):
        if i == 0:
            odd_even_vec[i] += bit%2
        else:
            k = i-1
            sub += bit * 2**k
            sub_max += 2**k
            odd_even_vec[i] += a_xor(bin_a, i, sub, sub_max)
        print(odd_even_vec, sub, sub_max)

    print("b")
    sub = 0
    sub_max = 0
    for i, bit in enumerate(bin_b):
        if i == 0:
            odd_even_vec[i] += bit%2
        else:
            k = i-1
            sub += bit * 2**k
            sub_max += 2**k
            odd_even_vec[i] += b_xor(bin_b, i, sub, sub_max)
            
        print(odd_even_vec, sub, sub_max)
        
    res = 0
    for i, bit in enumerate(odd_even_vec):
        res += bit%2 * 2**i

    print (res)

    
main()


Fixed submission:
def F(n):
    res = 0
    if n % 4 == 0:
        res = n
    elif n % 4 == 1:
        res = 1
    elif n % 4 == 2:
        res = 1^n
    else:
        res = 0
        
    return res

def main():
    A, B = map(int, input().split())
    ans = F(A-1) ^ F(B)

    #print(A, B, F(A-1), F(B))

    print(ans)

main()