Do Python objects originate from a common parent class?

according to Object Oriented Programming, every object created in Python must be an instance of a common parent class

This is not true. It happens that, in Objective-C, Java (and maybe C# too?), things tend to derive from a single superclass, but this is an implementation detail - not a fundamental of OO design.

OO design just needs a common-enough method to find the implementation of a method you wish to call on the object on which you wish to call it. This is usually fundamental to how the language works (C++, C#, Java, Objective-C, Python, etc all do it their own way that makes sense for their language).

In C++, this is done for static types by the linker and for dynamic types (through virtual inheritance) by a vector table -- no need for a common base class.

In Objective-C, this is done by looking up something in a hash-map on the object's class's structure, then calling a specific method to get the signature of the desired method. This code is nuanced, so everything generally derives from a single, common base-class.

Python technically shouldn't require this, but I think they've made an implementation choice to make everything be a class and every class derive from a common base class.

The common parent class in Python is object. In fact, although it's not mandatory in some versions, you should always declare your classes like this:

class MyClass(object):
  ...

In Python, all derive from the class type

this is why, whem creating a metaclass, we subclass type

class Meta(type):
    def __new__(cls, name, bases, attrs):
        <logic here>

class Foo(object):
    __metaclass__ = Meta

Also:

type(object) -> type
type(type) -> type

DynamicClass = type('DynamicClass', (Foo,), {'a': 1, 'b':2})

dyn = DynamicClass()
type(dyn) -> Foo

etc, etc

Well,

li = [1, 2, 3, 4]

class A:
  def __init__(self):
    pass

a = A()

print isinstance(a, object)
print isinstance(li, object)
print isinstance(5, object)

>> True
>> True
>> True

At some point in my life when I was confused about this, the following short tutorial helped me:

python objects and types

But if your confusion is more basic than this, then maybe you want to clarify which part of "everything is an object" you're having trouble with.