anchor.diff:        test/test_replaygain.py
     '';
   
  -  preCheck = ''
  -    (${concatMapStrings (s: "echo \"${s}\";") allPlugins}) \
  -      | sort -u > plugins_defined
  -    find beetsplug -mindepth 1 \
  -      \! -path 'beetsplug/__init__.py' -a \
  -      \( -name '*.py' -o -path 'beetsplug/*/__init__.py' \) -print \
  -      | sed -n -re 's|^beetsplug/([^/.]+).*|\1|p' \
  -      | sort -u > plugins_available
  -
  -    if ! mismatches="$(diff -y plugins_defined plugins_available)"; then
  -      echo "The the list of defined plugins (left side) doesn't match" \
  -           "the list of available plugins (right side):" >&2
  -      echo "$mismatches" >&2
  -      exit 1
  -    fi
  -  '';
  -
  -  # TODO: fix LOCALE_ARCHIVE for freebsd
  -  checkPhase = ''
  -    runHook 'preCheck'
  -
  -    LANG=en_US.UTF-8 \
  -    LOCALE_ARCHIVE=${glibcLocales}/lib/locale/locale-archive \
  -    BEETS_TEST_SHELL="${testShell}" \
  -    BASH_COMPLETION_SCRIPT="${completion}" \
  -    HOME="$(mktemp -d)"
  -    nosetests -v
  -    mkdir -p $HOME/
  -
  -    runHook 'postCheck'
  -  '';
  -
  -  installCheckPhase = ''
  -    runHook 'preInstallCheck'
  -
  -    tmphome="$(mktemp -d)"
  -
  -    EDITOR="${writeScript "beetconfig.sh" ''
  -      #!${stdenv.shell}
  -      cat > "$1" <<CFG
  -      plugins: ${concatStringsSep " " allEnabledPlugins}
  -      CFG
  -    ''}" HOME="$tmphome" "$out/bin/beet" config -e
  -    EDITOR=true HOME="$tmphome" "$out/bin/beet" config -e
  -
  -    runHook 'postInstallCheck'
  -  '';
  -
  -  doCheck = !isPy3;
  -  doInstallCheck = true;
  -
     meta = with lib; {
       description = "Music tagger and library organizer";
       homepage = http://beets.radbox.org;
  
positive.code:     werkzeug
    ] ++ optionals isPy2 [
      enum34
    ] ++ optionals (versionOlder pythonPackages.python.channel "3.5") [
      pathlib
    ] ++ [
      pycountry
  
negative.code: 
  let
    inherit (lib)
      optional
      optionals;
  
    completion = "${bash-completion}/share/bash-completion/bash_completion";
  
    version = "1.4.5";
  