public static function escape( $value, $escapeNull = true )
    {

        if( $value === null ) {
            return $escapeNull ? self::ESCAPE_CHARACTER . self::NULL_CHARACTER : '';
        }

        $value = str_replace( self::ESCAPE_CHARACTER, self::ESCAPE_CHARACTER . self::ESCAPE_CHARACTER, $value );
        $value = str_replace( self::RANGE_SEPARATOR, self::ESCAPE_CHARACTER . self::RANGE_SEPARATOR, $value );
        $value = str_replace( self::INTERVAL_SEPARATOR, self::ESCAPE_CHARACTER . self::INTERVAL_SEPARATOR, $value );

        return $value;

    }