code: def list_versions(self, project):
          
          url = self._build_url(constants.LIST_VERSIONS_ENDPOINT)
          params = {'project': project}
          json = self.client.get(url, params=params, timeout=self.timeout)
          return json['versions']
docs: Lists all deployed versions of a specific project. First class, maps
          to Scrapyd's list versions endpoint.