class_docstr: This signature is merely a CppSignature with Executorch types (optionally
  contains KernelRuntimeContext as well). The inline definition of
  CppSignature is generated in Functions.h and it's used by unboxing
  functions.
code: def returns_type(self) -> CType:
      return et_cpp.returns_type(self.func.returns)
  
file_path: pytorch/torchgen/executorch/api/types/signatures.py
imports: from dataclasses import dataclass
  from typing import List, Optional, Set
  import torchgen.api.cpp
  from torchgen.api.types import Binding, CType
  from torchgen.model import FunctionSchema, NativeFunction
  from .types import contextArg
  from torchgen.executorch.api import et_cpp
label_desc: Use image node_id 5 for calling the ExecutorchCppSignature obj's underlying member method code with example usage: obj.returns_type() and returns: et_cpp