code: func NewPlannedPermanode(key string) *Builder {
  	bb := base(1, "permanode")
  	bb.m["key"] = key
  	return bb
  }
docs: // NewPlannedPermanode returns a permanode with a fixed key.  Like
  // NewUnsignedPermanode, this builder is also not yet signed.  Callers of
  // NewPlannedPermanode must sign the map with a fixed claimDate and
  // GPG date to create consistent JSON encodings of the Map (its
  // blobref), between runs.