code: def _make_request(self, method, params):
          
          if self.blocked_until is not None and \
                  datetime.datetime.utcnow() < self.blocked_until:
              raise SlackError("Too many requests - wait until {0}" \
                      .format(self.blocked_until))
  
          url = "%s/%s" % (SlackClient.BASE_URL, method)
          params['token'] = self.token
          response = requests.post(url, data=params, verify=self.verify)
  
          if response.status_code == 429:
              # Too many requests
              retry_after = int(response.headers.get('retry-after', '1'))
              self.blocked_until = datetime.datetime.utcnow() + \
                      datetime.timedelta(seconds=retry_after)
              raise SlackError("Too many requests - retry after {0} second(s)" \
                      .format(retry_after))
  
          result = response.json()
          if not result['ok']:
              raise SlackError(result['error'])
          return result
docs: Make request to API endpoint
  
          Note: Ignoring SSL cert validation due to intermittent failures
          http://requests.readthedocs.org/en/latest/user/advanced/#ssl-cert-verification