class_docstr: Base class for all command-line options.
  
  To implement a new command-line option just inherit from this class.
  Then add the `flag` class-attribute to specify the name and a class
  docstring with the description.
  If your command-line option should take an argument you must also provide
  its name via the `arg` class attribute and its description as
  `arg_description`.
  Finally you need to implement the `execute` classmethod. It receives the
  value of the argument (if applicable) and the current run. You can modify
  the run object in any way.
  
  If the command line option depends on one or more installed packages, those
  should be imported in the `apply` method to get a proper ImportError
  if the packages are not available.
code: def get_short_flag(cls):
      if cls.short_flag is None:
          return "-" + cls.get_flag()[2]
      else:
          return "-" + cls.short_flag
  
imports: from typing import Callable
  import inspect
  import re
  from sacred.run import Run
  from sacred.commands import print_config
  from sacred.utils import convert_camel_case_to_snake_case
label_desc: Use image node_id 2 for calling the CommandLineOption obj's underlying member method code with example usage: obj.get_short_flag(cls) and returns: unknown, unknown