code: def update(self, title=None, body=None, state=None):
          
          data = {'title': title, 'body': body, 'state': state}
          json = None
          self._remove_none(data)
  
          if data:
              json = self._json(self._patch(self._api, data=dumps(data)), 200)
  
          if json:
              self._update_(json)
              return True
          return False
docs: Update this pull request.
  
          :param str title: (optional), title of the pull
          :param str body: (optional), body of the pull request
          :param str state: (optional), ('open', 'closed')
          :returns: bool