Question on classes in Python

[Nutty]

I am currently working on python and I just met a case which I find hard to understand:

Instance1 = class1 ()
Instance2 = Instance1.class2 ()

I adapted the trick (in fact it comes from panda 3D)

My question:
The 2nd row can really exist, if yes what is it (I do not understand the "Instance1.class2 ()")

I specify my problem a little, giving you the original in Panda 3D

# Load the panda actor, and loop its animation 
pandaActor = Actor.Actor("models/panda-model",{"walk":"models/panda-walk4"})
pandaActor.setScale (0.005,0.005,0.005) 
pandaActor.reparentTo (render) 
pandaActor.loop ("walk") 
#Create the four lerp intervals needed to walk back and forth
pandaPosInterval1= pandaActor.posInterval(13,Point3(0,-10,0), startPos=Point3(0,10,0))
pandaPosInterval2= pandaActor.posInterval(13,Point3(0,10,0), startPos=Point3(0,-10,0))
pandaHprInterval1= pandaActor.hprInterval(3,Point3(180,0,0), startHpr=Point3(0,0,0))
pandaHprInterval2= pandaActor.hprInterval(3,Point3(0,0,0), startHpr=Point3(180,0,0))

Actor is a class, so pandaActor is an instance of this class (line 2)
What I can not understand is:
pandaPosInterval1 = pandaActor.posInterval (........)
posInterval is also a class, I do not therefore: pandaActor.posInterval (........)
Practically, this I have no problem, I understand the trick, but at the theoretical level (pure Python), I do not know what this is.

[fellah]

look at the panda code ...

But there is much chance that Actor.posInterval is a method that simply return an instance of a class named Interval .

[Nutty]

Thank you for your reply, but the doc panda3d (reference), posInterval is listed in the classes and not methods! Hence my interrogation!

[fellah]

PosInterval != posInterval
The case is important.

I had a quick look on the doc panda3d and I did not find a method posInterval.
Is the code that you gave run the latest version of panda?

[Nutty]

Sorry for the box, it is PosInterval, and it is well documented in the classes (nothing in the functions and nothing in the methods) when my interrogation this is what: instance2 = Instance1.class2 (... )?
Also, this is the last version panda3D (software and doc)

[Ashok.M]

There is no "instance2 = instance1.class2 ()", it does absolutely nothing to say. There is just instance2 = instance1.method ()