def METHOD_NAME(self, target, interaction):
    """Return a callable for handling an interaction for a given target.
    This is a protected method expected to be implemented by a subclass.
    Parameters
    ----------
    target : any
        The UI target being operated on.
    interaction : any
        Any interaction object.
    Returns
    -------
    handler : callable(UIWrapper, interaction) -> any
        The function to handle the given interaction on a target.
    Raises
    ------
    InteractionNotSupported
        If the given target and interaction types are not supported
        by this registry.
    """