code/models/editablefields/EditableFieldMultipleOption.php
public function duplicate($doWrite = true)
    {
        $clonedNode = parent::duplicate($doWrite);

        if ($this->Options()) {
            foreach ($this->Options() as $field) {
                $newField           = $field->duplicate();
                $newField->ParentID = $clonedNode->ID;
                $newField->write();
            }
        }

        return $clonedNode;
    }
public function duplicate($doWrite = true)
    {
        $clonedNode = parent::duplicate($doWrite);

        if ($this->Options()) {
            foreach ($this->Options() as $field) {
                $newField           = $field->duplicate();
                $newField->ParentID = $clonedNode->ID;
                $newField->write();
            }
        }

        return $clonedNode;
    }
Duplicate a pages content. We need to make sure all the fields attached
to that page go with it.

@param bool $doWrite

@return DataObject