docstr: To check alivesness/authenticity of a peer
docstr_tok: ["To","check","alivesness\/authenticity","of","a","peer"]
code: def ping(
      self, context: AuthedServiceContext, challenge: bytes
  ) -> Union[bytes, SyftError]:
      """To check alivesness/authenticity of a peer"""
  
      # # Only the root user can ping the node to check its state
      # if context.node.verify_key != context.credentials:
      #     return SyftError(message=("Only the root user can access ping endpoint"))
  
      # this way they can match up who we are with who they think we are
      # Sending a signed messages for the peer to verify
      challenge_signature = context.node.signing_key.signing_key.sign(
          challenge
      ).signature
  
      return challenge_signature
  
imports: import secrets
  from typing import Any
  from typing import Callable
  from typing import List
  from typing import Optional
  from typing import Union
  from result import Result
  from ...abstract_node import NodeType
  from ...client.client import HTTPConnection
  from ...client.client import PythonConnection
  from ...client.client import SyftClient
  from ...node.credentials import SyftVerifyKey
  from ...node.worker_settings import WorkerSettings
  from ...serde.serializable import serializable
  from ...service.settings.settings import NodeSettingsV2
  from ...store.document_store import BaseUIDStoreStash
  from ...store.document_store import DocumentStore
  from ...store.document_store import PartitionKey
  from ...store.document_store import PartitionSettings
  from ...store.document_store import QueryKeys
  from ...types.grid_url import GridURL
  from ...types.transforms import TransformContext
  from ...types.transforms import keep
  from ...types.transforms import transform
  from ...types.transforms import transform_method
  from ...util.telemetry import instrument
  from ..context import AuthedServiceContext
  from ..data_subject.data_subject import NamePartitionKey
  from ..metadata.node_metadata import NodeMetadataV3
  from ..response import SyftError
  from ..response import SyftSuccess
  from ..service import AbstractService
  from ..service import SERVICE_TO_TYPES
  from ..service import TYPE_TO_SERVICE
  from ..service import service_method
  from ..user.user_roles import GUEST_ROLE_LEVEL
  from ..warnings import CRUDWarning
  from .node_peer import NodePeer
  from .routes import HTTPNodeRoute
  from .routes import NodeRoute
  from .routes import PythonNodeRoute
label_desc: Use image node_id 4 for calling the NetworkService obj's underlying member method code with example usage: obj.ping(context, challenge) and returns: challenge_signature