code: async def get_http_proxy(cls) -> typing.Optional[str]:
          
          data = await cls.get_config("http_proxy")
          return None if data is None or data == "" else data
docs: Proxy for APT and HTTP/HTTPS.
  
          This will be passed onto provisioned nodes to use as a proxy for APT
          traffic. MAAS also uses the proxy for downloading boot images. If no
          URL is provided, the built-in MAAS proxy will be used.