private function prepareBinaryExpression($operator, $left, $right)
    {
        return self::OPEN_BRACKET . $left . ' ' . $operator . ' ' . $right . self::CLOSE_BRACKET;
    }
private function prepareBinaryExpression($operator, $left, $right)
    {
        return self::OPEN_BRACKET . $left . ' ' . $operator . ' ' . $right . self::CLOSE_BRACKET;
    }
private function prepareBinaryExpression ( $ operator , $ left , $ right ) { return self :: OPEN_BRACKET . $ left . ' ' . $ operator . ' ' . $ right . self :: CLOSE_BRACKET ; }
To format binary expression.

@param string $operator The binary operator
@param string $left     The left operand
@param string $right    The right operand

@return string
To format binary expression .