code: def is_available(cls, url: str) -> bool:
      _is_available: bool = False
  
      ret = prometheus_client_parser is not None
      if not ret:
          wandb.termwarn(
              "Monitoring OpenMetrics endpoints requires the `prometheus_client` package. "
              "To install it, run `pip install prometheus_client`.",
              repeat=False,
          )
          return _is_available
      # check if the endpoint is available and is a valid OpenMetrics endpoint
      _session: Optional[requests.Session] = None
      try:
          assert prometheus_client_parser is not None
          _session = _setup_requests_session()
          response = _session.get(url, timeout=_REQUEST_TIMEOUT)
          response.raise_for_status()
  
          # check if the response is a valid OpenMetrics response
          # text_string_to_metric_families returns a generator
          if list(
              prometheus_client_parser.text_string_to_metric_families(
                  response.text
              )
          ):
              _is_available = True
      except Exception as e:
          logger.debug(
              f"OpenMetrics endpoint {url} is not available: {e}",
              exc_info=True,
          )
  
      if _session is not None:
          try:
              _session.close()
          except Exception:
              pass
      return _is_available
  
imports: import logging
  import re
  import sys
  import threading
  from collections import defaultdict, deque
  from functools import lru_cache
  from types import ModuleType
  from typing import TYPE_CHECKING, Dict, List, Mapping, Sequence, Tuple, Union
  import requests
  import requests.adapters
  import urllib3
  import wandb
  from wandb.sdk.lib import hashutil, telemetry
  from .aggregators import aggregate_last, aggregate_mean
  from .interfaces import Interface, Metric, MetricsMonitor
label_desc: Use image node_id 2 for calling the OpenMetrics obj's underlying member method code with example usage: obj.is_available(cls, url) and returns: _is_available, _is_available