class_docstr: A case-insensitive map of string keys to values.
  
  This is used by Python data source options to ensure consistent case insensitivity.
code: def __init__(self, *args: Any, **kwargs: Any) -> None:
      super().__init__(*args, **kwargs)
      self.update(*args, **kwargs)
  
imports: from abc import ABC, abstractmethod
  from collections import UserDict
  from typing import Any, Dict, Iterator, List, Sequence, Tuple, Type, Union, TYPE_CHECKING
  from pyspark.sql import Row
  from pyspark.sql.types import StructType
  from pyspark.errors import PySparkNotImplementedError
label_desc: Use image node_id 1 to create a new CaseInsensitiveDict object from inherited base classes: UserDict with example: obj = CaseInsensitiveDict()