Backpacking

#!/usr/bin/env python3

'''Backpacking'''

import sys

def backpacking(a, b):
    '''Backpacking challenge'''
    if a < 0:
        print('Error, A negative')
        return False
    if b > 10**6:
        print('Error, B too big')
        return False
    print(a + b)


def main():
    '''main'''
    a, b = sys.argv[1:]
    print(backpacking(a, b))

main()

Test 1

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 23, in <module>
    main()...

Test 2

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 23, in <module>
    main()...

Test 3

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 23, in <module>
    main()...

Test 4

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 23, in <module>
    main()...