python39Packages.livestreamer: cleanup, remove python2

pkgs/development/python-modules/livestreamer/default.nix

···
 { lib
 , buildPythonPackage
-, pkgs
 , fetchFromGitHub
 , isPyPy
+, makeWrapper
+, rtmpdump
 , pycrypto
 , requests
-, singledispatch ? null
-, futures ? null
 , isPy27
 }:
 
 buildPythonPackage rec {
+  pname = "livestreamer";
   version = "1.12.2";
-  pname = "livestreamer";
   disabled = isPyPy;
 
   src = fetchFromGitHub {
     owner = "chrippa";
     repo = "livestreamer";
-    rev = "v1.12.2";
+    rev = "v${version}";
     sha256 = "sha256-PqqyBh+oMmu7Ynly3fqx/+6mQYX+6SpI0Okj2O+YLz0=";
   };
 
-  nativeBuildInputs = [ pkgs.makeWrapper ];
+  nativeBuildInputs = [ makeWrapper ];
 
-  propagatedBuildInputs = [ pkgs.rtmpdump pycrypto requests ]
-    ++ lib.optionals isPy27 [ singledispatch futures ];
+  propagatedBuildInputs = [ rtmpdump pycrypto requests ];
 
   postInstall = ''
-    wrapProgram $out/bin/livestreamer --prefix PATH : ${pkgs.rtmpdump}/bin
+    wrapProgram $out/bin/livestreamer --prefix PATH : ${lib.makeBinPath [ rtmpdump ]}
   '';
 
   meta = with lib; {
     homepage = "http://livestreamer.tanuki.se";
-    description = ''
-      Livestreamer is CLI program that extracts streams from various
-      services and pipes them into a video player of choice.
-    '';
+    description = "Livestreamer is CLI program that extracts streams from various services and pipes them into a video player of choice";
     license = licenses.bsd2;
     maintainers = with maintainers; [ ];
   };