Writing effective and maintainable functions is essential for producing high-quality and maintainable Python code. Here are some best practices to consider:

• Use descriptive function names: Choose meaningful and descriptive names for your functions that accurately convey their purpose. This makes the code more readable and self-explanatory;
• Follow the single responsibility principle: Functions should have a single, well-defined responsibility. This improves code clarity, makes functions easier to understand, and promotes reusability;
• Keep functions short and focused: Functions should be concise and focused on a specific task. Long and complex functions are harder to understand, test, and maintain. If a function becomes too long, consider refactoring it into smaller, more manageable functions.

• Avoid excessive side effects: Minimize the use of global variables and mutable data structures within functions. Instead, aim for pure functions that take inputs and return outputs without modifying any external state. This makes the code more predictable and easier to test and debug;
• Use meaningful function parameters: Choose meaningful and intuitive names for function parameters. When appropriate, provide default values for optional parameters to enhance the flexibility and usability of your functions;
• Avoid unnecessary complexity: Keep your functions simple and straightforward. Don't overcomplicate them with unnecessary logic or excessive nesting. Strive for clarity and readability;
• Provide comments for your code. Comments help improve the readability of the code by providing additional context and explanations. They can clarify complex or obscure sections of code, describe the intent behind certain decisions, or provide warnings and notes about potential issues or caveats.

By following these best practices, you can write functions that are more effective, maintainable, and easily understandable by yourself and other developers working on the codebase.