code: def _retrieve_hosting_artifact_key(
      model_specs: JumpStartModelSpecs, instance_type: str
  ) -> str:
      """Returns instance specific hosting artifact key or default one as fallback."""
      instance_specific_hosting_artifact_key: Optional[str] = (
          model_specs.hosting_instance_type_variants.get_instance_specific_artifact_key(
              instance_type=instance_type
          )
          if instance_type
          and getattr(
              model_specs, "hosting_instance_type_variants", None
          )
          is not None
          else None
      )
  
      default_hosting_artifact_key: str = (
          model_specs.hosting_artifact_key
      )
  
      return (
          instance_specific_hosting_artifact_key
          or default_hosting_artifact_key
      )
  
file_path: sagemaker-python-sdk/src/sagemaker/jumpstart/artifacts/model_uris.py
imports: from __future__ import absolute_import
  import os
  from typing import Optional
  from sagemaker.jumpstart.constants import DEFAULT_JUMPSTART_SAGEMAKER_SESSION, ENV_VARIABLE_JUMPSTART_MODEL_ARTIFACT_BUCKET_OVERRIDE, JUMPSTART_DEFAULT_REGION_NAME
  from sagemaker.jumpstart.enums import JumpStartScriptScope
  from sagemaker.jumpstart.utils import get_jumpstart_content_bucket, get_jumpstart_gated_content_bucket, verify_model_region_and_return_specs
  from sagemaker.session import Session
  from sagemaker.jumpstart.types import JumpStartModelSpecs
label_desc: Use image node_id 2 for calling a global function with example usage: _retrieve_hosting_artifact_key(model_specs, instance_type) and returns: unknown