What is a backing store in the context of module io https://docs.python.org/3/library/io.html

[Peter Otten]

Veek M wrote:

> I was reading pydoc io and - how do I decipher the indentation?

$ cat demo.py
class Base: pass
class Sub(Base): pass
class SubSub(Sub): pass

class Other: pass
class OtherSub(Other, Base): pass
$ pydoc3.7 demo | head -n13
Help on module demo:

NAME
    demo

CLASSES
    builtins.object
        Base
            Sub
                SubSub
        Other
            OtherSub(Other, Base)

So indentation illustrates the class hierarchy; where this fails because of 
multiple inheritance the base classes are listed explicitly.