class_docstr: This class implements caching of values from the last use.
code: def get_metavar(self, param) -> str:
      param_name = param.envvar if param.envvar else param.name.upper()
      current_value = (
          read_from_cache_file(param_name)
          if not generating_command_images()
          else param.default.value
      )
      if not current_value:
          current_choices = self.choices
      else:
          current_choices = [
              f">{choice}<" if choice == current_value else choice
              for choice in self.choices
          ]
      choices_str = " | ".join(current_choices)
      # Use curly braces to indicate a required argument.
      if param.required and param.param_type_name == "argument":
          return f"{{{choices_str}}}"
  
      if param.param_type_name == "argument" and param.nargs == -1:
          # avoid double [[ for multiple args
          return f"{choices_str}"
  
      # Use square braces to indicate an option or optional argument.
      return f"[{choices_str}]"
  
imports: from __future__ import annotations
  import os
  import re
  from dataclasses import dataclass
  from typing import Any, Sequence
  import click
  from click import Context, Parameter, ParamType
  from airflow_breeze.utils.cache import check_if_values_allowed, read_and_validate_value_from_cache, read_from_cache_file, write_to_cache_file
  from airflow_breeze.utils.coertions import coerce_bool_value
  from airflow_breeze.utils.console import get_console
  from airflow_breeze.utils.recording import generating_command_images
  from airflow_breeze.utils.shared_options import set_dry_run, set_forced_answer, set_verbose
label_desc: Use image node_id 2 for calling the CacheableChoice obj's underlying member method code with example usage: obj.get_metavar(param) and returns: str, choices_str, str, str, choices_str, str, choices_str