docs: def list_requests(self, status=None, assignee=None, author=None):
          """
          Get all pull requests of a project.
          :param status: filters the status of the requests
          :param assignee: filters the assignee of the requests
          :param author: filters the author of the requests
          :return:
          """
          request_url = "{}pull-requests".format(self.create_basic_url())
  
          payload = {}
          if status is not None:
              payload['status'] = status
          if assignee is not None:
              payload['assignee'] = assignee
          if author is not None:
              payload['author'] = author
  
          return_value = self._call_api(request_url, params=payload)
          return return_value['requests']