class_docstr: LazyDefaultDict(default_factory[, ...]) --> dict with default factory
  
  The default factory is call with the key argument to produce
  a new value when a key is not present, in __getitem__ only.
  A LazyDefaultDict compares equal to a dict with the same items.
  All remaining arguments are treated the same as if they were
  passed to the dict constructor, including keyword arguments.
docstr: __missing__(key) # Called by __getitem__ for missing key; pseudo-code:
    if self.default_factory is None: raise KeyError((key,))
    self[key] = value = self.default_factory(key)
    return value
docstr_tok: ["__missing__","(","key",")","#","Called","by","__getitem__","for","missing","key",";","pseudo-code",":","if","self.default_factory","is","None",":","raise","KeyError","(","(","key",",",")",")","self","[","key","]","=","value","=","self.default_factory","(","key",")","return","value"]
code: def __missing__(self, key):
      """
      __missing__(key) # Called by __getitem__ for missing key; pseudo-code:
        if self.default_factory is None: raise KeyError((key,))
        self[key] = value = self.default_factory(key)
        return value
      """
      self[key] = self.default_factory(key)
      return self[key]
  
file_path: ray/python/ray/autoscaler/_private/aws/utils.py
imports: from collections import defaultdict
  from functools import lru_cache
  import boto3
  from boto3.exceptions import ResourceNotExistsError
  from boto3.resources.base import ServiceResource
  from botocore.client import BaseClient
  from botocore.config import Config
  from ray.autoscaler._private.cli_logger import cf, cli_logger
  from ray.autoscaler._private.constants import BOTO_MAX_RETRIES
label_desc: Use image node_id 1 for calling the LazyDefaultDict obj's underlying member method code with example usage: obj.__missing__(key) and returns: self