@function __keys-in($map: null) {
    @if __is-falsey($map) {
        @return ();
    }

    $map: __to-map($map);
    $skip-keys: __const('CONSTRUCTOR_KEYS');

    @return __without(map-keys($map), $skip-keys...);
}


@function __keys($map: null) {
    // currently the same as __keys-in
    @return __keys-in($map);
}


/// Creates a list of the own enumerable keys of `$map`.
///
///
/// @access public
/// @group Map
/// @param {Map} $map The map to inspect.
/// @returns {List} Returns the list of keys.
/// @example scss
/// // todo

@function _keys($args...) {
    @return call(get-function('__keys'), $args...);
}


/// Creates a list of the own and inherited enumerable keys of `map`.
/// **Note:** Non-map values are coerced to maps.
///
///
/// @access public
/// @group Map
/// @param {Map} $map The map to inspect.
/// @returns {List} Returns the list of keys.
/// @example scss
/// // todo

@function _keys-in($args...) {
    @return call(get-function('__keys-in'), $args...);
}