code: def _route_prefix_format(cls, v):
      """
      The route_prefix
      1. must start with a / character
      2. must not end with a / character (unless the entire prefix is just /)
      3. cannot contain wildcards (must not have "{" or "}")
      """
  
      if v is None:
          return v
  
      if not v.startswith("/"):
          raise ValueError(
              f'Got "{v}" for route_prefix. Route prefix must start with "/".'
          )
      if len(v) > 1 and v.endswith("/"):
          raise ValueError(
              f'Got "{v}" for route_prefix. Route prefix '
              'cannot end with "/" unless the '
              'entire prefix is just "/".'
          )
      if "{" in v or "}" in v:
          raise ValueError(
              f'Got "{v}" for route_prefix. Route prefix '
              "cannot contain wildcards, so it cannot "
              'contain "{" or "}".'
          )
  
      return v
  
imports: import logging
  from collections import Counter
  from dataclasses import dataclass, field
  from enum import Enum
  from typing import Any, Dict, List, Optional, Set, Union
  from zlib import crc32
  from ray._private.pydantic_compat import BaseModel, Extra, Field, root_validator, validator
  from ray._private.runtime_env.packaging import parse_uri
  from ray.serve._private.common import ApplicationStatus, DeploymentStatus, DeploymentStatusTrigger, ProxyStatus, ReplicaState, ServeDeployMode
  from ray.serve._private.constants import DEFAULT_GRPC_PORT, DEFAULT_UVICORN_KEEP_ALIVE_TIMEOUT_S, SERVE_DEFAULT_APP_NAME
  from ray.serve._private.deployment_info import DeploymentInfo
  from ray.serve._private.utils import DEFAULT
  from ray.serve.config import ProxyLocation
  from ray.util.annotations import PublicAPI
label_desc: Use image node_id 1 for calling a global function with example usage: _route_prefix_format(cls, v) and returns: v, v