code: def send(self):
          
          parse_links = self.parse_links or self.parse_markdown_links
  
          message = {
              'annotations': [],
              'entities': {
                  'parse_links': parse_links,
                  'parse_markdown_links': self.parse_markdown_links,
              }
          }
  
          if self.photo:
              photo, photo_meta = _upload_file(self.api, self.photo)
              message['annotations'].append({
                  'type': 'net.app.core.oembed',
                  'value': {
                      '+net.app.core.file': {
                          'file_id': photo.id,
                          'file_token': photo.file_token,
                          'format': 'oembed',
                      }
                  }
              })
  
          if self.attachment:
              attachment, attachment_meta = _upload_file(self.api, self.attachment)
              message['annotations'].append({
                  'type': 'net.app.core.attachments',
                  'value': {
                      '+net.app.core.file_list': [
                          {
                              'file_id': attachment.id,
                              'file_token': attachment.file_token,
                              'format': 'metadata',
                          }
                      ]
                  }
              })
  
          if self.text:
              message['text'] = self.text
          else:
              message['machine_only'] = True
  
          if self.headline:
              message['annotations'].append({
                  'type': 'net.app.core.broadcast.message.metadata',
                  'value': {
                      'subject': self.headline,
                  },
              })
  
          if self.read_more_link:
              message['annotations'].append({
                  'type': 'net.app.core.crosspost',
                  'value': {
                      'canonical_url': self.read_more_link,
                  }
              })
  
          return self.api.create_message(self.channel_id, data=message)
docs: Sends the broadcast message.
  
          :returns: tuple of (:class:`adnpy.models.Message`, :class:`adnpy.models.APIMeta`)