code: def __str__(self) -> str:
      message = f"{len(self._errors)} validation errors:\n"
      for err in self._errors:
          message += f"  {err}\n"
      return message
  
imports: from typing import Any, Dict, Optional, Sequence, Type, Union
  from pydantic import BaseModel, create_model
  from starlette.exceptions import HTTPException
  from starlette.exceptions import WebSocketException
  from typing_extensions import Annotated, Doc
label_desc: Use image node_id 2 for calling the ResponseValidationError obj's underlying member method code with example usage: obj.__str__() and returns: message