def add_entity(self):
        '''
        Add the entity. All the information got from the post data.
        '''
        post_data = self.get_post_data()

        if 'kind' in post_data:
            if post_data['kind'] == '1':
                self.add_pic(post_data)
            elif post_data['kind'] == '2':
                self.add_pdf(post_data)
            elif post_data['kind'] == '3':
                self.add_url(post_data)
            else:
                pass
        else:
            self.add_pic(post_data)
Add the entity. All the information got from the post data.