I don't know about the 1 item thing - subprocess shouldn't allow that. Consider:
```python
check_call(['ls', '--size --human-readable', '-1', '/tmp'])
CalledProcessError: Command '('ls', '--size --human-readable', '-1', '/tmp')' returned non-zero exit status 2
check_call(['ls', '--size', '--human-readable', '-1', '/tmp'])
0
```