A call to variables and functions between Python two classes

1.class_a ()

Class_b ()

2.class_b using variables and functions in Class_a

3. Variable class_a: class_a.num= ...

function Class_b: Instantiate the class_a first (if there is initialization in class_a, then it is also initialized at this time, in order to avoid the second initialization can not write initialization in the CLASS_A as the initialization function), and then call the function

The class_a variable used in the function called in the calling function must also be in Class_a: class_a.num= ... This form.

A call to variables and functions between Python two classes