code: function (name, value) {
  		var prop = this.getProperty(name);
  		var Constructor;
  		if (!prop) {
  			Constructor = this.getConstructor(name, value);
  			prop = new Constructor();
  			prop = this.setProperty(name, prop);
  		}
  		if (typeof value !== 'undefined') {
  			prop.set(value);
  		}
  		return prop;
  	}
docs: Declare the value of a single property
  @param {string} name Property name
  @param {*} value Property value
  @return {module:ok.Property} New property instance