What criteria can be used to determine the quality of written code?

The quality of Python code can be assessed based on several criteria:

• Readability: Code should be understandable by other developers, using clear variable and function names.
• Adherence to style: Follow PEP 8 — the official Python style guide.
• Simplicity and conciseness: Avoid unnecessary complexity, use built-in language features.
• No duplication: Repeated code should be refactored into functions or classes.
• Testability: Code should be easily covered by tests.
• Error handling: Proper use of exceptions and checks.
• Performance: Code should be efficient enough for the task.

Example:

# Bad

def f(x):
    return x*2

# Good

def double_number(number):
    """Doubles the input number."""
    return number * 2

Following these criteria helps create maintainable and high-quality code.