public function getOperator()
    {
        $this->setPrefixes();

        if ( ! empty($this->operator)) {
            return $this->operator;
        }

        if (in_array($this->getPrefix(), $this->smartPrefixes)) {
            $this->operator = 'SMART';
        } else if (in_array($this->getPrefix(), $this->globePrefixes)) {
            $this->operator = 'GLOBE';
        } else if (in_array($this->getPrefix(), $this->sunPrefixes)) {
            $this->operator = 'SUN';
        } else {
            $this->operator = 'UNKNOWN';
        }

        return $this->operator;
    }