code: @VisibleForTesting
    Path getWindowsPythonPath() {
      String cloudSdkPython = System.getenv("CLOUDSDK_PYTHON");
      if (cloudSdkPython != null) {
        Path cloudSdkPythonPath = Paths.get(cloudSdkPython);
        if (Files.exists(cloudSdkPythonPath)) {
          return cloudSdkPythonPath;
        } else {
          throw new InvalidPathException(cloudSdkPython, "python binary not in specified location");
        }
      }
  
      Path pythonPath = getPath().resolve(WINDOWS_BUNDLED_PYTHON);
      if (Files.exists(pythonPath)) {
        return pythonPath;
      } else {
        return Paths.get("python");
      }
    }
docs: https://github.com/GoogleCloudPlatform/appengine-plugins-core/issues/189