code: def _get_explicit_environ_credentials(
      target_audience: str | None,
  ) -> google_auth_credentials.Credentials | None:
      """Gets credentials from the GOOGLE_APPLICATION_CREDENTIALS environment variable."""
      explicit_file = os.environ.get(environment_vars.CREDENTIALS)
  
      if explicit_file is None:
          return None
  
      current_credentials = _load_credentials_from_file(
          os.environ[environment_vars.CREDENTIALS],
          target_audience=target_audience,
      )
  
      return current_credentials
  
file_path: airflow/airflow/providers/google/common/utils/id_token_credentials.py
imports: from __future__ import annotations
  import json
  import os
  from typing import TYPE_CHECKING
  import google.auth.transport
  from google.auth import credentials, environment_vars, exceptions
  from google.oauth2 import credentials, service_account
label_desc: Use image node_id 2 for calling a global function with example usage: _get_explicit_environ_credentials(target_audience) and returns: current_credentials, None