在嵌套函数中，我想调用内部函数

Question

我有一个名为 IrisData 的类。我在其中定义了一个函数作为描述。description 有多个我想要访问的子功能。我希望我的功能像如果调用描述，它应该返回描述中定义的每个函数。代码行：打印（I.description（））当调用内部函数时，它应该只返回内部函数。代码行：打印（I.description.attribute())*PFB 代码片段：class IrisData:    def urls(self):        self.url='https://archive.ics.uci.edu/ml/machine-learning-databases/iris/iris.data'        return self.url    def columns(self):        self.column_name=['sepal length','sepal width','petal length','petal width','class']        return self.column_name    def description(self):        def title():            self.titles ='Title: Iris Plants Database'            return self.titles        def source():            self.sources='''Sources:     \t(a) Creator: R.A. Fisher     \t(b) Donor: Michael Marshall ([e-mail])     \t(c) Date: July, 1988'''            return self.sources        def info():            self.descri='''Relevant Information:     \t--- This is perhaps the best known database to be found in the pattern recognition literature. Fisher's paper is a classic in the field and is referenced frequently to this day.  (See Duda & Hart, for example.     \t--- The data set contains 3 classes of 50 instances each, where each class refers to a type of iris plant. One class is linearly separable from the other 2; the latter are NOT linearly separable from each other.     \t--- Predicted attribute: class of iris plant.     \t--- This is an exceedingly simple domain.     \t--- This data differs from the data presented in Fishers article (identified by Steve Chadwick,  [e-mail] )     \tThe 35th sample should be: 4.9,3.1,1.5,0.2,"Iris-setosa"     \twhere the error is in the fourth feature.     \tThe 38th sample: 4.9,3.6,1.4,0.1,"Iris-setosa"     \twhere the errors are in the second and third features. '''            return self.descri        def attribute():            self.attri="""Attribute Information: