class Counter:
    def __init__(self):
        self.value = 0

    def increment(self):
        self.value += 1

counter = Counter()
counter.increment()
print(counter.value)  # Output: 1

1

import datetime

today = datetime.date.today()
print(today)

2026-01-14

class User:
    pass

user = User()

print(isinstance(user, User))  # True
print(type(user))              # <class '__main__.User'>

True
<class '__main__.User'>

print(5 + 10)          # Integer addition
print("Hello " + "AI") # String concatenation

15
Hello AI

class A:
    def process(self):
        print("Process A")

class B:
    def process(self):
        print("Process B")

class C(A, B):
    def process(self):
        A.process(self)
        B.process(self)

c = C()
c.process()

Process A
Process B

try:
    risky_operation()
except Exception as e:
    print("Error occurred:", e)

Error occurred: name 'risky_operation' is not defined

class AuthenticationError(Exception):
    pass

try:
    raise AuthenticationError("Invalid credentials")
except AuthenticationError as e:
    print("Login failed:", e)

Login failed: Invalid credentials

try:
    risky_operation()
except Exception as e:
    print("Error:", e)

Error: name 'risky_operation' is not defined

class InitialError(Exception):
    pass

class DerivedError(Exception):
    pass

try:
    try:
        raise InitialError("Initial failure")
    except InitialError as e:
        raise DerivedError("Follow-up failure") from e
except DerivedError as final_error:
    print(final_error)

Follow-up failure

import os

os.chdir("C:/Projects")
print(os.getcwd())

---------------------------------------------------------------------------

FileNotFoundError                         Traceback (most recent call last)

Cell In[1], line 3
      1 import os
----> 3 os.chdir("C:/Projects")
      4 print(os.getcwd())


FileNotFoundError: [WinError 2] The system cannot find the file specified: 'C:/Projects'