@mixin position ($position: relative, $coordinates: null null null null) {

@if type-of($position) == list {
  $coordinates: $position;
  $position: relative;
}

$coordinates: unpack($coordinates);

$top: nth($coordinates, 1);
$right: nth($coordinates, 2);
$bottom: nth($coordinates, 3);
$left: nth($coordinates, 4);

position: $position;

@if ($top and $top == auto) or (type-of($top) == number) {
  top: $top;
}

@if ($right and $right == auto) or (type-of($right) == number) {
  right: $right;
}

@if ($bottom and $bottom == auto) or (type-of($bottom) == number) {
  bottom: $bottom;
}

@if ($left and $left == auto) or (type-of($left) == number) {
  left: $left;
}

}