/// Remove leading `v` or `=` from $version, as well as spaces
/// @param {String} $version
/// @return {String}
/// @example scss
///   $version: clean('v1.2.3');
///   -> '1.2.3'
@function clean($version) {
  $version: _trim($version);

  @if index('v' '=', str-slice($version, 1, 1)) {
    @return clean(str-slice($version, 2));
  }

  @return $version;
}