Python ImportError在shell中返回0退出代码

Question

peters-mbp:python_proj me$ python api_tests.py

Traceback (most recent call last):
  File "/Users/me/python_proj/api_tests.py", line 2, in <module>
    import requestssss
ImportError: No module named requestssss


peters-mbp:python_proj me$ echo $?
0

如何让它返回非零退出代码？