public function getEmployees()
    {
        if ($this->_employees === null) {
            // Use the internal _getProperty() API to read the actual property.
            // NOTE: This function only throws if "employees" contains any
            // invalid non-basic data. Only basic PHP types are accepted.
            $this->_employees = $this->_getProperty('employees'); // Throws.
        }

        foreach ($this->_employees as &$value) {
            if (is_array($value)) {
                $value = new User($value); // Throws.
            }
        }

        return $this->_employees;
    }