code: def add_message(self, msg_content, folder, **kwargs):
          
          content = {'m': kwargs}
          content['m']['l'] = str(folder)
          content['m']['content'] = {'_content': msg_content}
  
          return self.request('AddMsg', content)
docs: Inject a message
  
          :params string msg_content: The entire message's content.
          :params string folder: Folder pathname (starts with '/') or folder ID