docs: def post(self, *args, **kwargs):
          """helper method for HTTP POST
  
          :param args:
          :param kwargs:
          :return: json response
          """
          try:
              resp = self.session.post(*args, **kwargs)
              if resp.status_code in _EXCEPTIONS_BY_CODE:
                  raise _EXCEPTIONS_BY_CODE[resp.status_code](resp.reason)
              if resp.status_code != requests.codes['ok']:
                  raise exceptions.Etcd3Exception(resp.reason)
          except requests.exceptions.Timeout as ex:
              raise exceptions.ConnectionTimeoutError(six.text_type(ex))
          except requests.exceptions.ConnectionError as ex:
              raise exceptions.ConnectionFailedError(six.text_type(ex))
          return resp.json()