code: def __enter__(self):
      return self
  
file_path: BigDL/python/chronos/src/bigdl/chronos/data/utils/prometheus_df.py
imports: import datetime
  import json
  from typing import Optional, Union
  from urllib.parse import urljoin
  import numpy
  import pandas
  import requests
  from bigdl.nano.utils.common import invalidInputError
label_desc: Use image node_id 2 for calling the Prometheus obj's underlying member method code with example usage: obj.__enter__() and returns: self