docs: def list_pull_requests(self, username, page, status=None):
          """
          List pull-requests filed by user.
  
          Params:
              username (string): filters the username of the user whose activity you are interested in.
              page (integer): the page requested. Defaults to 1.
              status (string): filter the status of pull requests. Default: Open,
                               can be Closed, Merged, All.
  
          Returns:
              list: A list of Pull-Requests filed by a given user for all the
                    projects for given Pagure instance.
          """
          request_url = "{}/api/0/user/{}/requests/filed".format(self.instance, username)
  
          payload = {}
          if username is not None:
              payload['username'] = username
          if page is not None:
              payload['page'] = page
          if status is not None:
              payload['status'] = status
  
          return_value = self._call_api(request_url, params=payload)
  
          return return_value['requests']