@function _get-value-type($v) {
  @if type-of($v) == list { $v: nth($v, 1); }
  @if type-of($v) == number and (unit($v) == s or unit($v) == ms) {
    @return t;
  }
  @if _is-a-css-property-name($v) {
    @return p;
  }
  @return e;
}

@function _determine-map-type($map) {
  @if map-get($map, _kf-map-type) != null {
    @return $map;
  }

  $level-1-map-keys: map-keys($map);
  $level-2-map-keys: map-keys(map-get($map, nth($level-1-map-keys, 1)));
  $level-3-map-keys: map-keys(map-get(map-get($map, nth($level-1-map-keys, 1)), nth($level-2-map-keys, 1)));

  $level-1-value-type: _get-value-type(nth($level-1-map-keys, 1));
  $level-2-value-type: _get-value-type(nth($level-2-map-keys, 1));
  $level-3-value-type: _get-value-type(nth($level-3-map-keys, 1));

  $_kf-map-type: $level-1-value-type + $level-2-value-type + $level-3-value-type + "v";
  @return map-merge($map, (_kf-map-type: $_kf-map-type));
}