text: import os
  from dataclasses import dataclass
  
  from query.prometheus import PrometheusClient
  from util.config import Config
  from util.request import Request
  
  
  @dataclass
  class TfServingConfig:
      url: str
  
      @staticmethod
      def from_env():
          url = os.getenv('TFSERVING_URL', None)
          if url is None:
              url = 'localhost:8500'
          return TfServingConfig(url)
  
  @dataclass
  class Context:
      client: PrometheusClient
      config: Config
      tfserving_config: TfServingConfig
      body: Request
  