Can I define optional packages in setuptools?
问题 Currently one of my packages requires a JSON parser/encoder, and is designed to use simplejson if available falling back to the json module (in the standard library) if necessary (as benchmarks show simplejson is faster). However, recently it's been hit & miss as to whether simplejson will install when using zc.buildout - something with the move to github, I believe. Which got me wondering; is it possible to define optional packages in my setup.py file which, if unavailable, won't stop the