determine if article is legacy

model.py

    def is_legacy(self):
        is_legacy = False
        temp = []

        if not self.image_attachments():
            if not self.image:
                temp.append(False)
            else:
                temp.append(True)
        else:
            temp.append(True)

        # remove duplicates
        temp = list(set(temp))

        # if no attachment images or key image
        if len(temp) == 1 and False in temp:
            is_legacy = True

        return is_legacy