class_docstr: A wrapper class that allows for easy interaction with a Study.
docstr: Computes a delay to the next attempt to poll the Vizier service.
  
  This does bounded exponential backoff, starting with $time_scale.
  If $time_scale == 0, it starts with a small time interval, less than
  1 second.
  
  Args:
      num_attempts: The number of times have we polled and found that the
          desired result was not yet available.
      time_scale: The shortest polling interval, in seconds, or zero.
          Zero is treated as a small interval, less than 1 second.
  
  Returns:
      A recommended delay interval, in seconds.
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code: def _polling_delay(self, num_attempts, time_scale):
      """Computes a delay to the next attempt to poll the Vizier service.
  
      This does bounded exponential backoff, starting with $time_scale.
      If $time_scale == 0, it starts with a small time interval, less than
      1 second.
  
      Args:
          num_attempts: The number of times have we polled and found that the
              desired result was not yet available.
          time_scale: The shortest polling interval, in seconds, or zero.
              Zero is treated as a small interval, less than 1 second.
  
      Returns:
          A recommended delay interval, in seconds.
      """
      small_interval = 0.3  # Seconds
      interval = max(time_scale, small_interval) * 1.41 ** min(
          num_attempts, 9
      )
      return datetime.timedelta(seconds=interval)
  
imports: import datetime
  import http
  import json
  import time
  from typing import Any, Dict, List, Mapping, Optional, Text, Union
  from googleapiclient import discovery
  from googleapiclient import errors
  import tensorflow
  from tensorflow_cloud.tuner import vizier_client_interface
  from tensorflow_cloud.tuner import constants
  from tensorflow_cloud.utils import google_api_client
label_desc: Use image node_id 11 for calling the _VizierClient obj's underlying member method code with example usage: obj._polling_delay(num_attempts, time_scale) and returns: datetime