code: def returns_str_pyi(signature: PythonSignature) -> str:
      field_names = namedtuple_fieldnames(signature.returns.returns)
      if field_names:
          return f"torch.return_types.{signature.name}"
  
      python_returns = [
          return_type_str_pyi(r.type) for r in signature.returns.returns
      ]
      if len(python_returns) > 1:
          return "Tuple[" + ", ".join(python_returns) + "]"
      if len(python_returns) == 1:
          return python_returns[0]
      return "None"
  
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 12 for calling a global function with example usage: returns_str_pyi(signature) and returns: str, str, signature, unknown, python_returns