final protected static function isOperatorValid (string $operator) : bool
	{
		// Arithmetic Operators
		$operators1 = ['+', '-', '*', '/', '%'];
		// Bitwise Operators
		$operators2 = ['&', '|', '^'];
		// Comparison Operators
		$operators3 = ['=', '<', '>', '>=', '<=', '<>'];
		// Compound Operators
		$operators4 = ['+=', '-=', '*=', '/=', '%=', '&=', '^-=', '|*='];
		// Logical Operators
		$operators5 = ['ALL', 'AND', 'ANY', 'BETWEEN', 'EXISTS', 'IN', 'LIKE', 'NOT', 'OR', 'SOME'];
		$operators 	= array_merge($operators1, $operators2, $operators3, $operators4, $operators5);
		return in_array(strtoupper($operator), $operators);
	}