anchor.diff:    pname = "pytest-timeout";
     version = "1.3.1";
   
  +  # remove after version 1.3.1
  +  patches = [
  +    (fetchpatch {
  +      name = "fix-installation-27-3-with-encoding-issue.patch";
  +      url = "https://bitbucket.org/pytest-dev/pytest-timeout/commits/9de81d3fc57a71a36d418d4aa181c241a7c5350f/raw";
  +      sha256 = "0g081j6iyc9825f63ssmmi40rkcgk4p9vvhy9g0lqd0gc6xzwa2p";
  +    })
  +  ];
  +
     src = fetchPypi {
       inherit pname version;
       sha256 = "4b261bec5782b603c98b4bb803484bc96bf1cdcb5480dae0999d21c7e0423a23";
     };
  +
     buildInputs = [ pytest ];
     checkInputs = [ pytest pexpect ];
     checkPhase = ''pytest -ra'';
  
positive.code:     description = "py.test plugin to abort hanging tests";
      homepage = https://bitbucket.org/pytest-dev/pytest-timeout/;
      license = licenses.mit;
      maintainers = with maintainers; [ makefu ];
    };
  }
  
negative.code: { buildPythonPackage
  , fetchPypi
  , fetchpatch
  , lib
  , pexpect
  , pytest
  