code: def is_none_expr(self) -> str:
      return f"_r.isNone({self.index})"
  
imports: from dataclasses import dataclass
  from typing import Dict, List, Optional, Sequence, Set, Tuple, Union
  from torchgen.api import cpp
  from torchgen.api.types import Binding, CppSignature, CppSignatureGroup
  from torchgen.gen import pythonify_default
  from torchgen.model import Argument, BaseTy, BaseType, FunctionSchema, ListType, NativeFunction, OptionalType, Return, Type, Variant
label_desc: Use image node_id 1 for calling the PythonArgParserOutputExpr obj's underlying member method code with example usage: obj.is_none_expr() and returns: str, self, str