private static void findSubdirInstallations(Collection<String> candidates, String rootDir, String dir_prefix, String exe_name) {
    VirtualFile rootVDir = LocalFileSystem.getInstance().findFileByPath(rootDir);
    if (rootVDir != null) {
      if (rootVDir instanceof NewVirtualFile) {
        ((NewVirtualFile)rootVDir).markDirty();
      }
      rootVDir.refresh(true, false);
      for (VirtualFile dir : rootVDir.getChildren()) {
        if (dir.isDirectory() && StringUtil.toLowerCase(dir.getName()).startsWith(dir_prefix)) {
          VirtualFile python_exe = dir.findChild(exe_name);
          if (python_exe != null) candidates.add(FileUtil.toSystemDependentName(python_exe.getPath()));
        }
      }
    }
  }
private static void findSubdirInstallations(Collection<String> candidates, String rootDir, String dir_prefix, String exe_name)