[Inkscape-user] command line fitCanvasToDrawing

Matplotlib produces pdf figures whose bounding boxes do not enclose all of the contents of the figure (or, usually, are too big).

I thought inkscape could easily solve this problem with:

inkscape -f matplotlibOutput.pdf --verb=FitCanvasToDrawing -A prettyfigure.pdf

But that leaves the pdf unchanged. Have I made a basic error?

Thanks, Chris