code: def reset_subscription_since(self, account_id, datetime_str):
          
          data = {
              'account_id': account_id,
              'datetime': datetime_str,
          }
          return self._perform_post_request(self.reset_subscription_since_endpoint, data, self.token_header)
docs: Handler for `--reset-subscription-since` command.
  
          Args:
              account_id(int): id of the account to reset.
              datetime_str(str): string representing the datetime used in the
                  next poll to retrieve data since.
  
          Returns:
              (str) json encoded response.
  
          NOTES:
              We don't care about validation here, we demand the responsibility to
              the backend.