def subtract_dict(current_dict: Any, updating_dict: Any) -> Dict:  # noqa: CCR001
    """
    Update one dict with another but with regard for nested keys.

    That way nested sets are unionised, dicts updated and
    only other values are overwritten.

    :param current_dict: dict to update
    :type current_dict: Dict[str, ellipsis]
    :param updating_dict: dict with values to update
    :type updating_dict: Dict
    :return: combination of both dicts
    :rtype: Dict
    """
    for key, value in updating_dict.items():
        old_key = current_dict.get(key, {})
        new_value: Optional[Union[Dict, Set]] = None
        if not old_key:
            continue
        if isinstance(value, set) and isinstance(old_key, set):
            new_value = old_key.difference(value)
        elif isinstance(value, (set, collections.abc.Mapping)) and isinstance(
            old_key, (set, collections.abc.Mapping)
        ):
            value = (
                convert_set_to_required_dict(value)
                if not isinstance(value, collections.abc.Mapping)
                else value
            )
            old_key = (
                convert_set_to_required_dict(old_key)
                if not isinstance(old_key, collections.abc.Mapping)
                else old_key
            )
            new_value = subtract_dict(old_key, value)

        if new_value:
            current_dict[key] = new_value
        else:
            current_dict.pop(key, None)
    return current_dict

    Update one dict with another but with regard for nested keys.

    That way nested sets are unionised, dicts updated and
    only other values are overwritten.

    :param current_dict: dict to update
    :type current_dict: Dict[str, ellipsis]
    :param updating_dict: dict with values to update
    :type updating_dict: Dict
    :return: combination of both dicts
    :rtype: Dict
    
ormar/queryset/utils.py