code: def fetch(self, R, pk, depth=1):
          "Request object from API"
          d, e = self._fetcher.fetch(R, pk, depth)
          if e: raise e
          return f fetch(self, R, pk, depth=1):
          "Request object from API"
          d, e = self._fetcher.fetch(R, pk, depth)
          if e: raise e
          return d
docs: Request object from API