class_docstr: Create a set of config values, optionally pre-filled with values from
  the given dictionary or pre-existing config object.
  
  The class implements the MutableMapping protocol keyed by option name (`str`).
  For convenience its methods accept either Option or str as the key parameter.
  
  .. seealso:: :meth:`set()`
  
  This config class is abstract because it needs its ``options`` class
  var to be set to an instance of :class:`Options` before it can be
  instanciated and used.
  
  .. code:: python
  
      class MyConfig(AbstractConfig):
          options = Options()
  
      MyConfig.register_option( "test:option_name", "This is an option", 0, int, lambda v: isinstance(v, int))
  
      cfg = MyConfig({"test:option_name": 10})
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code: def __getitem__(self, option_or_name: Union[Option, str]) -> Any:
      return self.get(option_or_name)
  
imports: from __future__ import annotations
  import logging
  from dataclasses import dataclass
  from typing import Any, Callable, ClassVar, Dict, Iterable, Mapping, MutableMapping, Optional, Set, Union
label_desc: Use image node_id 7 for calling the AbstractConfig obj's underlying member method code with example usage: obj.__getitem__(option_or_name) and returns: self