the output parameter‘s format is what?

[1999wen]

i want to know
"parser.add_argument("output", help="path to the output image")", the output parameter‘s format is what?
i set :
input
./原始图像.bmp
output
./yasuo.jpg"
it sent:
usage: encoder.py [-h] input output
encoder.py: error: unrecognized arguments: output ./yasuo.jpg

[elenacliu]

just remove the word input and directly follow your path