anchor.diff:  { stdenv
   , buildPythonPackage
   , fetchPypi
  +, isPy3k
   , numpy
   , scipy
   , matplotlib
  
positive.code: }:
  
  buildPythonPackage rec {
    name = "${pname}-${version}";
    pname = "nimfa";
    version = "1.3.1";
  
  
negative.code:   };
  
    propagatedBuildInputs = [ numpy scipy ];
    checkInputs = [ matplotlib pytest ];
    doCheck = !isPy3k;  # https://github.com/marinkaz/nimfa/issues/42
  
    meta = with stdenv.lib; {
      description = "Nonnegative matrix factorization library";
  