fix a silly bug in command line processing

1 job for master in 6 minutes and 15 seconds (queued for 1 second)
Status Name Job ID Coverage
  Build
failed build #78083

00:06:15

 
Name Stage Failure
failed
build Build
$ python3 file-demo.py
Traceback (most recent call last):
File "/builds/col0047/hand-detection/file-demo.py", line 3, in <module>
import cv2
File "/usr/local/lib/python3.9/dist-packages/cv2/__init__.py", line 5, in <module>
from .cv2 import *
ImportError: libGL.so.1: cannot open shared object file: No such file or directory
Cleaning up file based variables
ERROR: Job failed: exit code 1