private static Stream OpenFile(PlatformAdaptationLayer pal, string name, FileMode fileMode, FileAccess fileAccess, FileShare fileShare) {
if (pal.DirectoryExists(name)) {
// TODO: properly set errno
throw PythonOps.IOError("[Errno 13] Permission denied");
}
return pal.OpenInputFileStream(name, fileMode, fileAccess, fileShare);
}