private static function ensurePropertyExists($class, $name)
    {
        if (!array_key_exists($name, self::$properties[$class])) {
            throw new Exceptions\UnknownPropertyException(get_called_class(), $name);
        }
    }
private static function ensurePropertyExists($class, $name)
    {
        if (!array_key_exists($name, self::$properties[$class])) {
            throw new Exceptions\UnknownPropertyException(get_called_class(), $name);
        }
    }
private static function ensurePropertyExists ( $ class , $ name ) { if ( ! array_key_exists ( $ name , self :: $ properties [ $ class ] ) ) { throw new Exceptions \ UnknownPropertyException ( get_called_class ( ) , $ name ) ; } }
Determines if the property is a member of the class.

@param string $class The name of the class that we are checking for.
@param string $name The property name.
@throws UnknownPropertyException If the property does not exist.
Determines if the property is a member of the class .