code: def completions_response():
      return {
          "outputs": [
              "This is a test",
          ],
          "headers": {"Content-Type": "application/json"},
      }
  
imports: from unittest import mock
  import pytest
  from aiohttp import ClientTimeout
  from fastapi import HTTPException
  from fastapi.encoders import jsonable_encoder
  from pydantic import ValidationError
  from mlflow import MlflowException
  from mlflow.gateway.config import RouteConfig
  from mlflow.gateway.constants import MLFLOW_GATEWAY_ROUTE_TIMEOUT_SECONDS
  from mlflow.gateway.providers.mosaicml import MosaicMLProvider
  from mlflow.gateway.schemas import chat, completions, embeddings
  from mlflow.gateway.schemas.chat import RequestMessage
  from tests.gateway.tools import MockAsyncResponse
label_desc: Use image node_id 2 for calling a global function with example usage: completions_response() and returns: dict