anchor.diff: -{ lib, buildPythonPackage, fetchPypi, isPy3k
  +{ lib
  +, buildPythonPackage
  +, fetchPypi
  +, isPy3k
   , hypothesis
   , setuptools-scm
   , six
   , attrs
   , py
   , setuptools
  -, pytest-cov
   , pytest-timeout
   , pytest-tornado
   , mock
  
positive.code:     GitPython
      notebook
      jinja2
      ];
  
    meta = with lib; {
      homepage = "https://github.com/jupyter/nbdime";
  
negative.code:     sha256 = "67767320e971374f701a175aa59abd3a554723039d39fae908e72d16330d648b";
    };
  
    nativeBuildInputs = [ setuptools-scm ];
  
    propagatedBuildInputs = [
  