Functions organize code into reusable blocks.
def greet(name, greeting="Hello"):
return f"{greeting}, {name}!"
print(greet("Alice")) # Hello, Alice!
print(greet("Bob", "Hi")) # Hi, Bob!
# Multiple return values
def calculate(a, b):
return a + b, a - b, a * b
sum_val, diff, prod = calculate(10, 5)