anchor.diff:  
     pytestFlagsArray = [
       "--ignore=dev_tools"  # Only needed when developing new code, which is out-of-scope
  +    "--ignore=cirq/contrib/"  # requires external (unpackaged) python packages, so untested.
       "--benchmark-disable" # Don't need to run benchmarks when packaging.
     ];
     disabledTests = [
  
positive.code:     owner = "quantumlib";
      repo = "cirq";
      rev = "v${version}";
      sha256 = "0xs46s19idh8smf80zhgraxwh3lphcdbljdrhxwhi5xcc41dfsmf";
    };
  
    patches = [
      (fetchpatch {
        # Fixes serialization issues on certain versions of protobuf & numpy.
        name = "cirq-pr-2986-protobuf-bools.patch";
        url = "https://github.com/quantumlib/Cirq/commit/78ddfb574c0f3936f713613bf4ba102163efb7b3.patch";
        sha256 = "0hmad9ndsqf5ci7shvd924d2rv4k9pzx2r2cl1bm5w91arzz9m18";
      })
    ];
  
    postPatch = ''
      substituteInPlace requirements.txt \
        --replace "freezegun~=0.3.15" "freezegun" \
        --replace "matplotlib~=3.0" "matplotlib" \
        --replace "networkx~=2.4" "networkx" \
        --replace "numpy~=1.16, < 1.19" "numpy" \
        --replace "protobuf~=3.12.0" "protobuf"
    '';
  
    propagatedBuildInputs = [
  
negative.code:     # Seem to fail due to math issues on aarch64?
      "expectation_from_wavefunction"
      "test_single_qubit_op_to_framed_phase_form_output_on_example_case"
    ] ++ [
      # slow tests, for quicker building
      "test_anneal_search_method_calls"
      "test_density_matrix_from_state_tomography_is_correct"
      "test_example_runs_qubit_characterizations"
      "test_example_runs_hello_line_perf"
      "test_example_runs_bc_mean_field_perf"
      "test_main_loop"
      "test_clifford_circuit_2"
      "test_decompose_specific_matrices"
      "test_two_qubit_randomized_benchmarking"
      "test_kak_decomposition_perf"
      "test_example_runs_simon"
      "test_decompose_random_unitary"
      "test_decompose_size_special_unitary"
      "test_api_retry_5xx_errors"
      "test_xeb_fidelity"
      "test_example_runs_phase_estimator_perf"
      "test_cross_entropy_benchmarking"
    ];
  
    meta = with lib; {
  