assertNoneType(new NDict(null, null));
assertNoneType(new NEllipsis());
assertNoneType(new NExceptHandler(null, null, null));
assertNoneType(new NExec(null, null, null));
assertNoneType(new NExprStmt(null));
assertNoneType(new NFor(null, null, null, null));
assertNoneType(new NFunctionDef(null, null, null, null, null, null));
assertNoneType(new NGeneratorExp(null, null));
assertNoneType(new NGlobal(null));
assertNoneType(new NIf(null, null, null));
assertNoneType(new NIfExp(null, null, null));