anchor.diff:  { lib, fetchurl, makeWrapper
   , pypy2Packages
   , cvs, subversion, git, breezy
  +, installShellFiles
   }:
   
   pypy2Packages.buildPythonApplication  rec {
  
positive.code:     for i in bzr svn git; do
        wrapProgram $out/bin/cvs2$i \
            --prefix PATH : "${lib.makeBinPath [ cvs ]}"
      done
    '';
  
  
negative.code:     sha256 = "1ska0z15sjhyfi860rjazz9ya1gxbf5c0h8dfqwz88h7fccd22b4";
    };
  
    nativeBuildInputs = [ makeWrapper installShellFiles ];
  
    checkInputs = [ subversion git breezy ];
  
  