anchor.diff:  
   buildPythonPackage rec {
     pname = "cirq-core";
  -  version = "0.13.1";
  +  version = "0.14.1";
   
     disabled = pythonOlder "3.6";
   
  
positive.code:     freezegun
    ];
  
    pytestFlagsArray = lib.optionals (!withContribRequires) [
      # requires external (unpackaged) libraries, so untested.
      "--ignore=cirq/contrib/"
    ];
    disabledTests = [
      "test_metadata_search_path" # tries to import flynt, which isn't in Nixpkgs
  
negative.code:     owner = "quantumlib";
      repo = "cirq";
      rev = "v${version}";
      sha256 = "sha256-cIDwV3IBXrTJ4jC1/HYmduY3tLe/f6wj8CWZ4cnThG8=";
    };
  
    sourceRoot = "source/${pname}";
  
    postPatch = ''
      substituteInPlace requirements.txt \
        --replace "matplotlib~=3.0" "matplotlib" \
        --replace "networkx~=2.4" "networkx" \
        --replace "numpy~=1.16" "numpy" \
        --replace "sympy<1.10" "sympy"
    '';
  
    propagatedBuildInputs = [
  