Just a note that we'll probably have to wrap the binaries that are in this module when we finish making the guix package:
mediagoblin/media_types/pdf/processing.py I see that pdftocairo, pdfinfo, and unoconv probably need to be wrapped to point to the executable that is in /gnu/store. See this issue for a similar discussion about wrapping binaries with guix: https://issues.guix.gnu.org/50833
