code: public Map<String, String> newKeys() {
  		Map<String, String> keys = getEntity(invokePost("_newkeys", null), Map.class);
  		if (keys != null && keys.containsKey("secretKey")) {
  			this.secretKey = keys.get("secretKey");
  		}
  		return keys;
  	}
docs: Generates a new set of access/secret keys.
  Old keys are discarded and invalid after this.
  @return a map of new credentials