code: def _merge_tag_lines(existing_tag, new_table_info):
      if existing_tag is None:
          return new_table_info
      if new_table_info in existing_tag:
          return existing_tag
      return "\n".join([existing_tag, new_table_info])
  
imports: import concurrent.futures
  import logging
  import sys
  import threading
  import uuid
  from py4j.java_gateway import CallbackServerParameters
  import mlflow
  from mlflow import MlflowClient
  from mlflow.exceptions import MlflowException
  from mlflow.spark import FLAVOR_NAME
  from mlflow.tracking.context.abstract_context import RunContextProvider
  from mlflow.utils import _truncate_and_ellipsize
  from mlflow.utils.autologging_utils import ExceptionSafeClass, autologging_is_disabled
  from mlflow.utils.databricks_utils import get_repl_id
  from mlflow.utils.validation import MAX_TAG_VAL_LENGTH
label_desc: Use image node_id 3 for calling a global function with example usage: _merge_tag_lines(existing_tag, new_table_info) and returns: str, new_table_info, existing_tag