return appearance

 # populated by `return_appearance`
    appearance_template = """
    {header}
    |c\n{name}|n
    {desc}
    {exits}{characters}{things}
    {footer}
        """

    def return_appearance(self, looker, **kwargs):
        """
        Main callback used by 'look' for the object to describe itself.
        This formats a description. By default, this looks for the `appearance_template`
        string set on this class and populates it with formatting keys
            'name', 'desc', 'exits', 'characters', 'things' as well as
            (currently empty) 'header'/'footer'.

        Args:
            looker (Object): Object doing the looking.
            **kwargs (dict): Arbitrary, optional arguments for users
                overriding the call. This is passed into the helper
                methods and into `get_display_name` calls.

        Returns:
            str: The description of this entity. By default this includes
                the entity's name, description and any contents inside it.

        Notes:
            To simply change the layout of how the object displays itself (like
            adding some line decorations or change colors of different sections),
            you can simply edit `.appearance_template`. You only need to override
            this method (and/or its helpers) if you want to change what is passed
            into the template or want the most control over output.

        """

        if not looker:
            return ""

        # ourselves
        name = self.get_display_name(looker, **kwargs)
        desc = self.db.desc or "Description non définie."

        # contents
        content_names_map = self.get_content_names(looker, **kwargs)
        exits = list_to_string(content_names_map["exits"])
        characters = list_to_string(content_names_map["characters"])
        things = list_to_string(content_names_map["things"])

        # populate the appearance_template string. It's a good idea to strip it and
        # let the client add any extra spaces instead.
        return self.appearance_template.format(
            header="",
            name=name,
            desc=desc,
            exits=f"|wExits:|n {exits}" if exits else "",
            characters=f"\n|wPersonnages:|n {characters}" if characters else "",
            things=f"\n|wAgents:|n {things}" if things else "",
            footer="",
        ).strip()