PHPWarrior\Position::normalize_direction PHP Method

    public static function normalize_direction($direction)
    {
        return str_replace(':', '', $direction);
    }

 public function perform($direction = 'backward')
 {
     $direction = \PHPWarrior\Position::normalize_direction($direction);
     $this->verify_direction($direction);
     $this->unit->position->rotate(array_search($direction, self::$ROTATION_DIRECTIONS));
     $this->unit->say(sprintf(__("pivots %s"), __($direction)));
 }