whole_func_string: function(name, value, pos) {
  			var element = this.get(name);
  			if (element)
  				return element.value(value);
  			
  			if (!_.isUndefined(value)) {
  				// no such element — create it
  				return this.add(name, value, pos);
  			}
  		}
func_code_string: function(name, value, pos) {
  			var element = this.get(name);
  			if (element)
  				return element.value(value);
  			
  			if (!_.isUndefined(value)) {
  				// no such element — create it
  				return this.add(name, value, pos);
  			}
  		}
func_documentation_string: Returns or updates element value. If such element doesn't exists,
  it will be created automatically and added at the end of child list.
  @param {String} name Element name or its index
  @param {String} value New element value
  @returns {String}