Lesson 15 — Prompt templates as functions

Stop retyping good prompts

Once you have a prompt that works well, do not retype it every time — make it a function. The parts that change become parameters; the parts that stay the same are written once.

def explain_prompt(code, level="beginner"):
    return f"Explain this Python code at {level} level, line by line:\n{code}"

A default parameter (level="beginner") is used when you do not pass a value, so the common case stays short and the special case is still possible: explain_prompt(code, level="expert").

Benefits: every prompt has the same good structure, you can improve the template in one place, and you can test it like any other function.

Why it matters: this is how prompts live inside real apps — as code, with parameters, reviewed and tested like the rest of the program.