static function isValid($unit, $throw = false)
    {
        if (in_array($unit, static::getUnits(), true)) {
            return true;
        }

        if ($throw) {
            throw new InvalidArgumentException("Invalid unit '$unit'.");
        }

        return false;
    }
static function isValid($unit, $throw = false)
    {
        if (in_array($unit, static::getUnits(), true)) {
            return true;
        }

        if ($throw) {
            throw new InvalidArgumentException("Invalid unit '$unit'.");
        }

        return false;
    }
static function isValid ( $ unit , $ throw = false ) { if ( in_array ( $ unit , static :: getUnits ( ) , true ) ) { return true ; } if ( $ throw ) { throw new InvalidArgumentException ( "Invalid unit '$unit'." ) ; } return false ; }
Returns whether the given unit is valid.

@param string $unit
@param bool   $throw

@return bool
Returns whether the given unit is valid .