>>> import subprocess
>>> subprocess.Popen('/some/nonexistent/thing')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/kwilson/Python/CPython-2.7.10/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/Users/kwilson/Python/CPython-2.7.10/lib/python2.7/subprocess.py", line 1335, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory