anchor.diff: -{ stdenv, fetchFromGitHub, autoreconfHook, coreutils, pkgconfig
  +{ stdenv, autoreconfHook, coreutils, fetchFromGitHub, fetchpatch, pkgconfig
   # pyflame needs one python version per ABI
   # are currently supported
   # * 2.6 or 2.7 for 2.x ABI
   # * 3.4 or 3.5 for 3.{4,5} ABI
  -# * 3.6        for 3.6+ ABI
  -# if you want to disable support for some ABI, make the corresponding argument null
  -, python2, python35, python36, python3
  +# * 3.6        for 3.6 ABI
  +# * 3.7        for 3.7+ ABI
  +# to disable support for an ABI, make the corresponding argument null
  +, python2, python35, python36, python37, python3
   }:
   stdenv.mkDerivation rec {
     pname = "pyflame";
  
positive.code:     sha256 = "0hz1ryimh0w8zyxx4y8chcn54d6b02spflj5k9rcg26an2chkg2w";
    };
  
    nativeBuildInputs = [ autoreconfHook pkgconfig ];
    buildInputs = [ python36 python2 python35 ];
  
    postPatch = ''
      patchShebangs .
  
negative.code:   '';
  
    postInstall = ''
      install -D utils/flame-chart-json $out/bin/flame-chart-json
    '';
  
    doCheck = true;
    # reproduces the logic of their test script, but without downloading pytest
    # from the internet with pip
    checkPhase = let inherit (stdenv) lib; in
      lib.concatMapStringsSep "\n" (python: ''
        set -x
        PYMAJORVERSION=${lib.substring 0 1 python.version} \
          PATH=${lib.makeBinPath [ coreutils ]}\
          PYTHONPATH= \
          ${python.pkgs.pytest}/bin/pytest tests/
        set +x
      '') (lib.filter (x: x != null) buildInputs);
  
    meta = with stdenv.lib; {
      description = "A ptracing profiler for Python ";
      longDescription = ''
        Pyflame is a high performance profiling tool that generates flame graphs
        for Python. Pyflame uses the Linux ptrace(2) system call to collect
        profiling information. It can take snapshots of the Python call stack
        without explicit instrumentation, meaning you can profile a program
        without modifying its source code.
      '';
      homepage = https://github.com/uber/pyflame;
      license = licenses.asl20;
  