code: function(class_path, default_namespace) {
  
  		if (!(class_path in this.constructors) && default_namespace) {
  
  			class_path = default_namespace + '.' + class_path;
  
  		}
  
  		return this.constructors[class_path];
  
  	}
docs: Get class constructor
  @param {string} class_path Full name of a class, or a short name (if namespace is provided)
  @param {string} [default_namespace] The default prefix where to search for the class, like <str>"Lava.widget"</str>
  @returns {function}