What will be the output of the following Python code?class Demo: def __init__(self): self.a = 1 self.__b = 1  def display(self): return self.__b obj = Demo()print(obj.__b)

The code will raise an AttributeError. This is because __b is a private variable, and it cannot be accessed directly outside of its class, Demo.

In Python, variables that start with double underscores __ are considered as private variables. They are used to encapsulate (hide) the data from the outside world (outside of the class they are defined).

So, when you try to access obj.__b, Python will raise an AttributeError saying 'Demo' object has no attribute '__b'.

If you want to access the value of __b, you should use the display method defined in the class Demo, like this: print(obj.display()). This will print 1, which is the value of __b.

The code will raise an AttributeError. This is because '__b' is a private variable. In Python, variables that start with double underscores are considered private for the class they are declared in and cannot be accessed directly outside the class.

Here's the step by step explanation:

1. A class named 'Demo' is defined with an initializer method (init), which sets 'a' to 1 and '__b' also to 1. The variable 'a' is public and '__b' is private due to the double underscores.

2. A method named 'display' is defined which returns the value of the private variable '__b'.

3. An object 'obj' of the class 'Demo' is created.

4. When you try to print 'obj.__b', it will raise an AttributeError saying 'Demo' object has no attribute '__b'. This is because '__b' is private and cannot be accessed directly outside the class.

If you want to access the value of '__b', you should use the 'display' method of the class 'Demo' like this: print(obj.display()). This will print '1' as the output.