code: def register_config(
      name,
      title,
      *,
      default=_NotGiven,
      default_fn=_NotGiven,
      description=None,
      # yes, we shadow type, this is OK
      type=_NotGiven,
      # for manual entry
      dialog=None,
      scope=_NotGiven,
  ):
      """Register a configuration item
  
      This function can be used by DataLad extensions and other client
      code to register configurations items and their documentation with
      DataLad's configuration management. Specifically, these definitions
      will be interpreted by and acted on by the `configuration` command,
      and `ConfigManager.obtain()`.
  
      At minimum, each item must be given a name, and a title. Optionally, any
      configuration item can be given a default (or a callable to compute a
      default lazily on access), a type-defining/validating callable (i.e.
      `Constraint`), a (longer) description, a dialog type to enable manual
      entry, and a configuration scope to store entered values in.
  
      Parameters
      ----------
      name: str
        Configuration item name, in most cases starting with the prefix
        'datalad.' followed by at least a section name, and a variable
        name, e.g. 'datalad.section.variable', following Git's syntax for
        configuration items.
      title: str
        The briefest summary of the configuration item's purpose, typically
        written in the style of a headline for a dialog UI, or that of an
        explanatory inline comment just prior the item definitions.
      default: optional
        A default value that is already known at the time of registering the
        configuration items. Can be of any type.
      default_fn: callable, optional
        A callable to compute a default value lazily on access. The can be
        used, if the actual value is not yet known at the time of registering
        the configuration item, or if the default is expensive to compute
        and its evaluation needs to be deferred to prevent slow startup
        (configuration items are typically defined as one of the first things
        on import).
      description: str, optional
        A longer description to accompany the title, possibly with instructions
        on how a sensible value can be determined, or with details on the
        impact of a configuration switch.
      type: callable, optional
        A callable to perform arbitrary type conversion and validation of value
        (or default values). If validation/conversion fails, the callable
        must raise an arbitrary exception. The `str(callable)` is used as
        a type description.
      dialog: {'yesno', 'question'}
        A type of UI dialog to use when manual value entry is attempted
        (only in interactive sessions, and only when no default is defined.
        `title` and `description` will be displayed in this dialog.
      scope: {'override', 'global', 'local', 'branch'}, optional
        If particular code requests the storage of (manually entered) values,
        but defines no configuration scope, this default scope will be used.
  
      Raises
      ------
      ValueError
        For missing required, or invalid configuration properties.
      """
      kwargs = dict(
          default=default, default_fn=default_fn, scope=scope, type=type
      )
      kwargs = {k: v for k, v in kwargs.items() if v is not _NotGiven}
      if dialog is not None and not title:
          raise ValueError("Configuration dialog must have a title")
      doc_props = dict(title=title)
      if description:
          doc_props["text"] = description
      # dialog is OK to be None, this is not just about UI, even if
      # the key of the internal data structure seems to suggest that.
      # it is also the source for annotating config listings
      kwargs["ui"] = (dialog, doc_props)
      _definitions[name] = _ConfigDefinition(**kwargs)
  
label_desc: Use image node_id 1 for calling a global function with example usage: register_config(name, title) without return types