Doubt Regarding object

Sir, you mentioned that in python, there is nothing like primitive data type and everything is an object, That’s why we can define function inside a function. But I am unable to relate this concept with C++ where we defined objects using classes. Here if everything is an object, don’t we have to specify the name of the class before accessing it?

-First there are 4 primitive data types
Integer float string Boolean
-Also in c++ we can define nested function using lambda expressions
-also we use classname() to initialise objects in python ; python being an interpretered language after execution of class keep the instance of class in the memory