code: def retrieve_diaspora_host_meta(host):
      
      document, code, exception = fetch_document(host=host, path="/.well-known/host-meta")
      if exception:
          return None
      xrd = XRD.parse_xrd(document)
      return xrd
docs: Retrieve a remote Diaspora host-meta document.
  
      :arg host: Host to retrieve from
      :returns: ``XRD`` instance