code: function wash(obj) {
  	if (!obj) {
  		return {};
  	}
  
  	var keys = Object.keys(obj);
  	for (var i = 0; i < keys.length; i++) {
  		var key = keys[i];
  
  		if (obj[key] === undefined) {
  			delete obj[key];
  		}
  	}
  
  	return obj;
  }
docs: Removes properties that are undefined. That makes node-couchbase happy. Hopefully some day, they
  won't be as strict with undefined.
  
  @param {Object} obj