anchor.diff:  { stdenv
   , buildPythonPackage
   , fetchPypi
  -, isPy3k
  -, isPy38
  +, isPy27
   # python dependencies
   , click
  -, configparser ? null
   , dateutil
   , etelemetry
   , filelock
   , funcsigs
   , future
  -, futures
   , mock
   , networkx
   , nibabel
   , numpy
   , packaging
  -, pathlib2
   , prov
   , psutil
   , pybids
  
positive.code:     simplejson
      traits
      xvfbwrapper
    ] ++ stdenv.lib.optionals (!isPy3k) [
      configparser
      futures
      pathlib2 # darwin doesn't receive this transitively, but it is in install_requires
    ];
  
    checkInputs = [
  
negative.code: , callPackage
  }:
  
  let
  
   # This is a temporary convenience package for changes waiting to be merged into the primary rdflib repo.
  