In Python, functions are first-class objects, which means you can treat them like any other variable. You can:

• assign them to variables,
• store them in data structures, and
• pass them as arguments to other functions.

Here’s a simple example

def greet(name):
    return f"Hello, {name}!"

def shout(name):
    return f"HELLO, {name.upper()}!"

# This function takes another function as a parameter
def call_with_name(func, name):
    return func(name)

# Passing 'greet' as a parameter
print(call_with_name(greet, "Alice"))  # Output: Hello, Alice!

# Passing 'shout' as a parameter
print(call_with_name(shout, "Bob"))    # Output: HELLO, BOB!

Key idea

When you pass a function as an argument, you pass the function object itself — not the result of calling it.
That’s why we pass greet, not greet().

You can even use lambda functions for quick, inline behavior:

print(call_with_name(lambda n: f"Hi there, {n}!", "Charlie"))
# Output: Hi there, Charlie!

Would you like me to show how to return a function from another function too (that’s called a higher-order function)?