code: function setNewKey(_newKey) {
  			if ( rangeName ) {
  				/**
  				 * If the model has a range attribute, _newKey must be an object that contains
  				 * the hash and range attributes.
  				 */
  				_.extend( changed, _newKey );
  			} else {
  				/**
  				 * If the model doesn't have a range attribute, _newKey must be the value of the hash attribute.
  				 */
  				changed[ hashName ] = _newKey;
  			}
  
  			// Add the new key attribute(s) to the Item to be sent to DynamoDB
  			_.extend( params.Item, options.serializeDates === true ? serializeAllDates( model, _.clone( changed ) ) : changed );
  		}
docs: Convenience method to set the `newKey` attribute(s), once it's generated.