anchor.diff:  
     disabledTestPaths = [
       "tests/test_stellar.py" # requires stellar-sdk
  +    "tests/test_firmware.py" # requires network downloads
     ];
   
     pythonImportsCheck = [ "trezorlib" ];
  
positive.code:     attrs
      click
      construct
      ecdsa
      hidapi
      libusb1
  
negative.code: 
  buildPythonPackage rec {
    pname = "trezor";
    version = "0.13.4";
  
    disabled = !isPy3k;
  
    src = fetchPypi {
      inherit pname version;
      sha256 = "04a77b44005971819386bbd55242a1004b1f88fbbdb829deb039a1e0028a4af1";
    };
  
    nativeBuildInputs = [ installShellFiles ];
  