Quick Answer

Proper way to define functions in Python.

Understanding the Issue

Python functions are defined using the def keyword, with parameters in parentheses. Functions can have docstrings, type hints (Python 3.5+), and default arguments. Proper indentation is crucial.

The Problem

This code demonstrates the issue:

Python Error 
-- Need to define a function to calculate area

The Solution

Here's the corrected code:

Python Fixed 
-- Basic function
def rectangle_area(width, height):
    """Calculate area of rectangle."""
    return width * height

-- With type hints and defaults
def circle_area(radius: float = 1.0) -> float:
    """Calculate area of circle."""
    return 3.14159 * radius ** 2

Key Takeaways

Use docstrings and type hints for better maintainability.