class_docstr: Cache that converts Pygments tokens into `prompt_toolkit` style objects.
  
  ``Token.A.B.C`` will be converted into:
  ``class:pygments,pygments.A,pygments.A.B,pygments.A.B.C``
class_docstr_tok: ["Cache","that","converts","Pygments","tokens","into","`","prompt_toolkit","`","style","objects",".","``","Token.A.B.C","``","will","be","converted","into",":","``","class",":","pygments",",","pygments.A",",","pygments.A.B",",","pygments.A.B.C","``"]
code: def __missing__(self, key: tuple[str, ...]) -> str:
      result = "class:" + pygments_token_to_classname(key)
      self[key] = result
      return result
  
imports: from __future__ import annotations
  import re
  from abc import ABCMeta, abstractmethod
  from typing import TYPE_CHECKING, Callable, Dict, Generator, Iterable, Tuple
  from prompt_toolkit.document import Document
  from prompt_toolkit.filters import FilterOrBool, to_filter
  from prompt_toolkit.formatted_text.base import StyleAndTextTuples
  from prompt_toolkit.formatted_text.utils import split_lines
  from prompt_toolkit.styles.pygments import pygments_token_to_classname
  from .base import Lexer, SimpleLexer
label_desc: Use image node_id 1 for calling the _TokenCache obj's underlying member method code with example usage: obj.__missing__(key) and returns: result